Nicholas William Tschoegl (1918-2011) was born in what is now an eastern part of the Czech Republic. He was educated in Europe and after the Second World War his family fled to Australia and later to USA where he became a Professor of Chemical Engineering, although pursuing additional interests in ancient civilisation and the development of writing. He has also lectured on Atlantis supporting the idea of Minoan Crete and Thera as its possible location(a).*He follows Galanopoulos & Bacon in subscribing to the ‘factor ten’ hypothesis to reconcile Plato’s apparent date for the Atlantean war with the eruption of Thera.*
R(ich) McQuillen is an American investigator who has cogently argued for an Egyptian location for Atlantis. He has diligently gathered an impressive array of evidence from classical writers including Hellanicus, Solinus and Aeschylus to support his view and arranged the morass that is Greek mythology to construct a credible timeframe for the Atlantis narrative.
McQuillen places the Pillars of Heracles at Canopus, which was formerly in the Western Nile delta but is now submerged about 6.5 km from the coast in the Bay of Aboukir. He is also of the opinion that the Egyptians used lunar ‘years’ rather than solar years bringing the backdrop to the Atlantis story into the 2nd millennium BC.*However, he now seems to favour the ‘factor ten’ interpretation of Plato’s date.*
McQuillen locates Atlantis at Pharos, which was near modern Alexandria. His website(a) is well worth a visit.
Extensive underwater excavations in the region have been undertaken in recent years by Franck Goddio and his team with remarkable results(b).
It is also worth noting that the late Ulf Richter reasoned that a river delta was the most likely topographical setting for Atlantis.
Factor Ten is a term I have employed to describe the fact that so many of the numbers in Plato’s Atlantis story, referring to time, physical dimensions and population all appear to be exaggerations, but would be more credible if reduced by a factor of ten. The date of 9600 BC for a war between Atlantis and Athens is not compatible with the Bronze Age description given by Plato, the dimensions of the canals in the city of Atlantis suggest a profligate degree of over-engineering and the size of the Atlantean army, as recorded, is comparable to the numerical strength of today’s USA’s military. On top of that, there is no archaeological evidence to support the idea of Athens having anything more than a Stone Age culture in the 10th millennium BC.
Dr A. G. Galanopoulos, who spent years excavating on Santorini, alsosuggested that all numbers in the thousands in Plato’s text were exaggerated, during translation, by a factor of ten. One can be forgiven for thinking that he was prompted to do this in order to match Atlantis to the timeframe of the Theran eruption, which occurred about 900 years before Solon’s Egyptian trip. However, J. V. Luce and Dorothy Vitaliano have refuted this idea.
A more frequently suggested explanation for the conflict between the 9,000 years given by Plato and the Bronze Age backdrop is that a lunar rather than a solar calendar was utilised by the Egyptian priests which would bring the two elements more into phase. So perhaps ‘Factor Twelve’ might be a more appropriate appellation.
Eudoxus of Cnidos (c.408-355 BC) who also studied astronomy with the priests of Heliopolis in Greece was one of the first to suggest that the Ancient Egyptians used lunar cycles to measure time. The idea was later endorsed by the Egyptian priest Manetho, Plutarch and Diodorus Siculus. Centuries later, Francisco Cervantes de Salazar (1514-1575) in his Crónica de la Nueva España he was a firm supporter of the idea of interpreting Plato’s 9,000 ‘years’ as lunar cycles, echoing the earlier statement of Eudoxus.*A year later Olof Rudbeck proposed the same explanation.*
However, while the substitution of solar years with lunar cycles would give a date for the Atlantean war that is more compatible with conventional archaeology, it still leaves the apparently inflated dimensions and military numbers recorded by Plato, unexplained. Since all of Plato’s numbers, in the Atlantis narrative appear to be overstated by a similar amount it would seem appropriate to invoke the application of Occam’s Razor(c), which leads to an exaggeration by a factor of ten as the most likely explanation!
The use of lunar rather than solar units might explain the unrealistic ages ascribed to biblical characters such as Adam, Methuselah, or Noah although close study does not address all the difficulties. Similar problems exist with the length of the reign of individual Sumerian kings. My belief is that a common explanation will eventually be found to rationalise both sets of anomalies. The answer will probably include the application of the Sumerian use of a numeric base of 60, coupled with lunar, solar and the Egyptian use of three seasonal ‘years’ per solar year. Zoltán Simon has claimed that the ages of the patriarchs were calculated using 90-day ‘years’[0549.7].
A number of suggestions have been put forward to explain how Plato’s exaggerated numbers came to be. Georgeos Diaz-Montexanocontends that it was not any confusion over hieroglyphics that led to the a tenfold exaggeration of numbers but the fact that in the spoken language of the Egyptians 100 and 1000 can be easily confused.
What may be of relevance is the fact that the Cretan scripts known as Linear A and Linear B use similar numbering signs. The number 100 is designated by a circle whereas 1000 is a circle with four nipples known as excrescences at the cardinal points. Both James Mavor and Rodney Castleden have advocated the idea that it was a misreading of these Minoan numerals that led to Plato recording hundreds as ‘thousands’.
Another reason for considering a factor ten error in Plato’s numbers may be drawn from the Chicago Demotic Dictionary, which has been developed over the past three decades at the Oriental Institute of the University of Chicago. It is edited by Professor Janet H. Johnson and is concerned with the ancient Egyptian cursive script in use from circa 650 BC, which is around the time of Solon, until the 5th century AD. Their website reveals that the cursive numerals for hundreds only differ from thousands by having longer tails(b) . I note that Johnson also records “that thousands sometimes had longer tails than expected”(p.23). This offers another credible explanation for how a transcription error could increase numbers by a factor of ten, which would bring Plato’s dates into conformity with other details in his Atlantis story, namely the Bronze Age milieu so clearly described there.
I also note that the Greeks had no zero or decimal point in their number system, making this kind of tenfold mistake quite a credible one(a).
Angelos Georgiou Galanopoulos (1910- 2001) was a Greek seismologist with the Athens Seismological Institute. To a great extent his views on Atlantis are based on the work of Spyridon Marinatos. Dr. Galanopoulos’ best known work on Atlantis  was co-authored with the British archaeologist Edward Bacon. This book offers probably the best argument in support of the Minoan Hypothesis. In 1960 he listed 19 of Plato’s statements that could be related to Minoan Crete or Thera. The geologist Dorothy Vitaliano considered this list in her book and thought that up to 14 of them ‘could be made to fit’ Plato’s description. Francis Hitching also refers to this list in the work he edited on world mysteries[307.137], while personally supporting a Minoan influence on Plato’s account[578.166].
Dr. Galanopoulos was a supporter of the idea that the Egyptian hieroglyphic for 100 was misread as 1000 and so decreased all numbers in Plato’s text by factor of ten. This explanation does not stand up to scrutiny, as the Egyptian hieroglyphics are distinctly different and in any case the Egyptian priests who presumably would have a clear understanding of their own inscriptions would have carried out the interpretation.
Immanuel Velikovsky also proposed a factor ten reduction of Plato’s 9,000 years in 1950[037.152], although he was not certain regarding the specific source of the error. My own study of Plato’s large numbers in the Atlantis narrative led me to also conclude that all of them made more sense is reduced by a factor of ten, but a definitive explanation of how this may have occurred has so far eluded me (see: Factor Ten).
In December 1969, the classical scholar, Moses I. Finley (1912-1986), wrote a critical review of ‘Atlantis’ for The New York Review of Books(a), to which Galanopoulos responded(b).
Dating the Atlantis War is one of the most contentious difficulties faced by Atlantology. The critical problem is to identify the time of the Atlantean War and that of the later destruction of Atlantis itself; two events apparently separated by a time span not recorded by Plato. This entry is only concerned with the date of the war. However, it should be pointed out that Plato also reveals that the Atlantis story has a very long history before the war, back to a time when ships and sailing did not yet exist (Crit.113e), so it is understandable when Plato filled the historical gap with mythological characters, namely fijves sets of twins sired by Poseidon. Of course, Poseidon being a sea god did not require a boat to get to the island of Atlantis! Plato also informs us that the twins and their descendants lived on the island for ‘many generations’ and extended their rule over many other islands in the sea (Crit.114c).
There are roughly three schools of thought regarding this important detail. The first group persist in accepting at face value Plato’s reference to a period of 9,000 solar years having elapsed since the War with Atlantis up to the time of Solon’s visit around 550 BC. The second group are convinced that the 9,000 refers to periods other than solar years, such as lunar cycles or seasons. The third group seeks to identify the time of Atlantis by linking it to other known historical events.
[1.0] 9550 BC is factually correct
This view has a slowly dwindling number of supporters among serious investigators. In order to defend this date they cite a wide range of evidence to suggest the existence of advanced cultures in the 10th millennium BC. Matters such as an earlier than conventionally accepted date for the Sphinx, early proto-alphabets a la Glozel or apparently anomalous structures such as the Lixus foundations or the controversial Baalbek megaliths have all been recruited in order to support an early date for Atlantis, many, if not all, have their dates hotly disputed. Apart from the contentious dates there is NOTHING to definitively link any of them with Plato’s Atlantis.
In common with most nations, the Egyptians competitively promoted the great antiquity of their own origins. Herodotus reports that while in Egypt he was told of a succession of kings extending over 17,000 years. The priests of Memphis told him firmly that 341 kings and a similar number of high priests had until then, ruled their country. (Herodotus, Book II, 142). Even an average reign of 20 years would give a total of nearly 7000 years whereas a more improbable 26-year average would be required to span the necessary 9000 years.
It is therefore obvious that the 17,000 years related to Herodotus is not credible raising a question regarding the trustworthiness of the 9000 years told to Solon.
In The Laws Plato refers to Egyptian art going back 10,000 years, seemingly, indicating a consistency in his belief in great antiquity of civilisation and fully compatible with his date for Atlantis. However, I have discovered that in Plato’s time ‘ten thousand’ was frequently used simply to express a large but indefinite number.
A Bible study site tells us that “The use of definite numerical expressions in an indefinite sense, that is, as round numbers, which is met with in many languages, seems to have been very prevalent in Western Asia from early times to the present day.”(h)
The acceptance of Plato’s 9,000 years as literally correct defies both commonsense and the archaeological evidence, which demonstrates that neither Athens nor a structured Egypt existed at such an early period.
[2.0] 9000 refers to units of time other than solar years
Advocates of this view, understandably point out, that the Atlantis described in such detail by Plato belongs to the Bronze Age and could not have existed at an earlier date. It is worth noting that the technology is coincidental with the most advanced known to Plato and his audience. For those who argue that mankind has been destroyed on one or more occasion and has had to start again from scratch, it is not credible that if this was the case, that the culture and technology described by Plato as existing in 9500 BC is precisely what he would have experienced himself. There is nothing in the Atlantis texts to connect it with a pre-Bronze Age society, nor is there anything to suggest any technology or cultural advance beyond that of the 4th century BC. Plato’s tale tells of the existence of at least three major nations before the destruction of Atlantis: Egypt, Athens and Atlantis itself. There is no archaeological evidence to indicate anything other than Neolithic cultures existing in Egypt or Athens around 9500 BC. In fact, the currently accepted date for the beginning of Egyptian civilisation is circa 3100 BC and also for the existence of a primitive culture around Athens at about the same time. This would parallel the time of the western European megalithic builders.
*It is noteworthy that researchers who support a 9,600 BC date for the war between Atlantis and Athens cannot explain how this took place millennia before there was any structured society in Greece.*
It may be worth noting the comments of Israel Finkelstein and Neil Silberman who have argued for a 7thcentury BC date for the final draft of the Exodus narrative rather than during the 2nd millennium BCas suggested by the text.
“In much the same way that European illuminated manuscripts of the Middle Ages depicted Jerusalem as a European city with turrets and battlements in order to heighten its direct impact on contemporary readers” (p68). Similarly, it is quite possible that Plato added architectural and technological details of his day to a more ancient tale of a lost civilisation in order to make a more powerful impression on his audience.
According to Bury’s translation, Plato mentions (Crit. 119e) that iron was used for utensils and weapons in Atlantis and so forcing us to look to a date later than 2000 BC for its destruction. Olaf Rudbeck spotted this reference around 1700.
Diaz-Montexano claims that the ‘9000 years’ in Critias has been mistranslated. He refers to the earliest versions of Critias that are available and insists that the texts permit a translation of either ‘9 times in a 1000 years’ or ‘1009’, the first being the more rational! Frank Joseph has also used this 1009 number, quoting private correspondence from Kenneth Caroli, in his 2015 regurgitation of Atlantis and 2012. Diaz-Montexano has also drawn attention to the commentary on Timaeus by Proclus,writing in the 5th century AD, where he treats Plato’s use of 9000 as having symbolic rather than literal meaning. It should also be kept in mind that many cultures, ancient and modern use specific numbers to indicate indefinite values(e).
[2.2] In June 2017, a forum on the Historum.com website included the following possible explanation for the Atlantean dates:
“ The date 8000 is given as a fraction of 8 since the Greeks commonly used fractional notation. Plato wrote in 400 BC and Solon obtained the account in 570 BC.
No Egyptian Annals ever went back 9000 or even 8000 years. The furthest back the Egyptian annals went at the time of Herodotus was to 3050 BC to the reign of Menes the first Pharaoh who Herodotus knew about. Therefore it is obvious that the number of years has been given as a fraction which was extremely common in Greek numerology.
Thus the war between Atlantis and Athens occurred in 9000/8 + 570 = 1695 BC (+/-63 years) which is pretty close to the date of the war between the Titans and the Gods c.1685-1675 BC. The entire story of Atlantis runs concurrent to the time of the Thera Eruption. You even have 10 kings ruling the land equivalent to the 12 Titans.”
The bible too denotes years as fractions, i.e. seasons, equinoxes/solstices etc. That is why you have biblical patriarchs that lived 800 and 900 year old. The ages to Noah are all counted in Lunar months.”(i)
While I’m aware that the Egyptians also had a different way of dealing with fractions, I really cannot fully understand the suggestion made above.
[2.3] 900 not 9000 years
In order to address these apparent conflicts, some have suggested that the stated 9000 years, which allegedly elapsed since the catastrophe, are the result of incorrect transcription by someone along what is a very long chain of transmission and that hundreds have somehow been confused with thousands and that the correct figure should be 900 years. Another suggestion is that the Egyptian hieroglyphics for ‘hundred’ and ‘thousand’ are easily confused. This explanation does not hold water, as there is little room for confusion between these hieroglyphics as illustrated below.
However, 900 years earlier than Solon would place the conflict with the Atlanteans during the XVIIIth Dynasty and would have been well recorded. More recently Diaz-Montexano put forward the idea that the Egyptian words for ‘100’ and ‘1000’ when spoken sounded similar leading to Solon’s error. This idea has now been taken up by James Nienhuis and in greater detail by R. McQuillen(a) .
Another explanation offered by James W. Mavor Jnr. is that the original Egyptian story emanated from Crete where it may have been written in either the Linear A or Linear B script where the symbols for 100 and 1000 are quite similar. In both scripts the symbol for 100 is a circle whereas the symbol for 1000 is a circle with four equally spaced small spikes or excrescences projecting outward.
Nevertheless, the most potent argument against the ‘factor ten’ solution is that if the priests did not intend to suggest that Egypt was founded 8000 years before Solon’s visit but had actually meant 800 years, it would place the establishment of Egypt at around 1450 BC, which is clearly at variance with undisputed archaeological evidence. However, I contend that they were referring to the establishment of Sais as a centre of importance, not the foundation of the entire nation of Egypt.
[2.4] 9000 months not years
As early as 1572 Pedro Sarmiento de Gamboa suggested the application of lunar ‘years’ rather than solar years to Plato’s figures. Augustin Zárate expressed the same view in 1577, quoting Eudoxus in support of it.
Then there are others, such as Émile Mir Chaouat and Jürgen Hepke who subscribe to the view that the 9000 ‘years’ recorded by Plato referred to months rather than solar years, as the early Egyptians extensively used a lunar calendar and in fact continued to use it throughout their long history, particularly for determining the dates of religious festivals and since Solon received the Atlantis story from Egyptian priests it would be understandable if they used lunar ‘years’ in their conversations. Eudoxus of Cnidos (c.400 BC- c. 350 BC), mathematician and astronomer, who spent a year in Egypt, declared, “The Egyptians reckon a month as a year”. Diodorus Siculus (1st cent. BC) echoes this statement. (see Richard A. Parker) and Manetho (3rd cent.BC) (Aegyptiaca[1373.40])
This use of months rather than years would give us a total of just 750 years before Solon’s visit and so would place the Atlantis catastrophe around 1300 BC, nearly coinciding with the eruption of Thera and the collapse of the Minoan civilisation.
A similar explanation as been offered by J.Q. Jacobs to rationalise the incredible time spans found in ancient Indian literature, who suggested that numbers referred to days rather than years(b).
[2.5] 5,000 not 9,000 years
A claim was made on Graham Hancock’s website in 2008(c) that Plato did not write 9,000 but instead wrote 5,000, but that the characters for both were quite similar leading to the misunderstanding. This claim was apparently originally made by Livezeanu Mihai. However, my reading of Greek numerals makes this improbable as 9,000 requires five characters ( one for 5,000 and one for each of the other four thousands), while 5,000 needs just the one.
[3.1] Sometime after 9500 BC.
Jonas Bergmancorrectly points out that according to the story related by the priests of Sais to Solon,the Egyptian civilisation was founded 1000 years after Athens was first established in 9600 BC. Although this probably just refers to the founding of the city of Sais rather than the early Egyptian state.
Plato describes the original division of the earth between the gods of old, Poseidon got Atlantis and Athena got Greece. The implication is that both were founded at the same time, namely 9600 BC. Realistically, the 9000 year time span is better treated as an introductory literary cliché such as ‘once upon a time’ or the Irish ‘fado, fado’ (long, long ago). Plato’s text describes the building of Atlantis and informs us that no man could get to the island ‘for ships and voyages were not yet’. Since Atlantis had twelve hundred warships at the time of the conflict with Athens, the war could not have taken place in 9600 BC. The development of seafaring and shipbuilding would have taken a considerable time. Bergman concludes that the war with Atlantis took place long after 9600 BC.
*Another date was proposed by Otto Muck  in 1976, when he maintained that Atlantis had been situated in the Atlantic and was destroyed by an asteroidal impact in 8498 BC and proposed that the same event also created the Carolina Bays!*
[3.2] Peter James as quoted in Francis Hitching’s The World Atlas of Mysteries[307.138] is reported to have accepted the orthodox date of 3100 BC as the start of Egyptian civilisation and considering the priest’s statement that the events outlined took place one thousand years before the creation of Egypt and so added only 500 years to compensate for nationalistic exaggeration and has concluded that 3600 BC is a more realistic date for the destruction of Atlantis.
[3.3] Early in the 20th century, the German scholar Adolf Schulten and the classicist H. Diller from Kiel, both advocated an even more radical date of around 500 BC, having identified the narrative of Plato as paralleling much of the Persian wars (500-449 BC) with the Greeks. This however would be after Solon’s trip to Egypt and have made little sense of Plato’s reference to him.
[3.4] 4015 BC is the precise date offered by Col. Alexander Braghine who credits the destruction of Atlantis to a close encounter with Halley’s Comet on the 7th June in that year. This is close to the date favoured by deGrazia.
[3.5] 3590-1850 BChas been suggested by the Czech writer Radek Brychta who has developed an ingenious idea based on the fact that the Egyptians who were so dependent on the Nile, divided their year into three seasons related to their river, the flooding, the blossom and the harvest periods. Brychta points out that counting time by seasons rather than solar years was common in the Indus civilisation that occupied part of modern Pakistan. Even today Pakistan has three seasons, cool, hot and wet. Brychta contends that the 9000 ‘years’ related to Solon were in fact seasons and should be read by us as 3000 years which when added to the date of Solon’s Egyptian visit would give an outside date of 3590 BC. If Brychta is correct this 9000 year/season corruption could easily have occurred during the transmission and translation of the story during its journey from the Indus to the Nile valley.
[3.6] 3100 BC asa date for the destruction of Atlantis has been proposed by a number of investigators including, David Furlong, Timo Niroma, and Duncan Steel. Hossam Aboulfotouh has proposed a similar 3070 BC as the date of Atlantis’ demise(f).
[3.7] 2200 BCis the proposed date put forward by Dr. Anton Mifsud for the end of Atlantis, located in the vicinity of his native Malta. He arrived at this conclusion after studying the comments of Eumelos of Cyrene who dated the catastrophe to the reign of King Ninus of Assyria. Around the same time, in Egypt, unusually low Nile floods led to the collapse of centralised government and generations of political turmoil(f). According to some commentators(g) the Los Millares culture also ended around the same time.
[3.8] 1200 BC is a date favoured by investigators such as Frank Joseph, Eberhard Zangger and Steven Sora. It is dependent on the acceptance of Plato’s 9000 ‘years’ being lunar rather than solar. It is worth noting that this date has also been linked to the suggested close encounter with the Phaëton comet and its destructive effects globally.
[3.9] More than one Atlantis!
It is not unreasonable to consider Plato’s Atlantis narrative as a literary amalgam of two or more historically based stories or myths. One possibility is that the Egyptian priests related to Solon the tale of the inundation of a powerful and advanced culture in the dim and distant past. Such an event did occur, worldwide, when the Ice Age glaciers melted, resulting, for example, in the eastern Atlantic, the flooding the North Sea, the Celtic Shelf and dramatically reducing in size the Canaries and the Azores and creating the British Isles. Obviously, the entire world was affected by this event, so that there were also major inundations in the West Indies and the South China Sea. However, events off the coasts of Europe and Africa would be more likely to become part of folklore on this side of the Atlantic.
[4.0] My own preference is to treat the use of 9000 by Solon/Plato as an expression of a large but indefinite number or an exaggeration by a factor of ten. At the beginning of my research I strongly favoured the former, but as I proceeded to investigate other aspects of Plato’s Atlantis story, I realised that virtually all other large numbers used by him also appeared to be inflated by a comparable amount. In seeking a solution to this I found myself drawn to Occam’s Razor, which states that where there are competing theories, the simpler is to be preferred.
It is worth noting that the Egyptian hieratic numerals also stopped with the highest value, expressed by a single character, being 9000. However, having studied the matter more closely I am reluctantly drawn to the ‘factor ten’ theory. This I have written about at some length in Joining the Dots.
The 1st millennium BC saw the introduction and gradual development of new writing and numerical systems by the Greeks. Some claim that the Greeks borrowed the Egyptian numbers(k).
At an early stage 9000 was the highest number expressed by a single character in Greek, which in time came to be used to denote a large but uncertain value. As the needs of commerce and science demanded ever higher numbers a new character ‘M’ for myriad with a value of 10,000 was introduced. It also was used to indicate a large indefinite number, a practice that continues to this very day. Greek numerical notation was still being developed during Plato’s life.
Today, we use similar expressions such as ‘I have a million things to do’ with no intention of being taken literally, but simply to indicate ‘many’(e). It is unfortunate that this interpretation of 9,000 does little to pinpoint the date of the Atlantean war, but it is not unreasonable to attribute a value to it of something in excess of 1,000 and possibly a multiple of it.
However, having said that, I am also attracted to the ’factor ten’ theory after a study of other numbers in the Atlantis narrative which all seem to be consistently exaggerated by a similar amount, which seems to be a factor of ten!
Andrew Collins in his Gateway to Atlantis[072.52] wrote “a gross inconsistency has crept into the account, for although Critias affirms that Athens’ aggressor came from ‘without’ the Pillars of Hercules, the actual war is here said to have taken place ‘nine thousand years’ before the date of the dialogue, c.421 BC. This implies a date in the region of 9421 BC, which is not what was stated in the Timaeus. Here 9000 years is the time that has elapsed between the foundation of Athens and Solon’s visit to Sais c. 570 BC. Since Egypt was said to have been founded a full thousand years later, and the ‘aggressor’ rose up against both Athens and Egypt, it provides a date post 8570 BC. These widely differing dates leave us with a glaring anomaly that defies explanation. The only obvious solution is to accuse Plato of a certain amount of sloppiness when compiling the text.”
Collins’ suggestion of ‘sloppiness’ is made somewhat redundant if my suggestion that Plato was using 9,000 as a large, but indefinite idiomatic value, could be substantiated.
The late Ulf Richter was quite unwilling to accept Plato’s 9,000 years as reliable after a close study of the relevant texts.
Others have produced evidence to suggest that this period in the Earth’s history saw one or more major catastrophic events that may or may not have been interconnected; (i) a collision or near miss with an extraterrestrial body, (ii) a pole shift, (iii) the melting of the glaciers of the last Ice Age and the consequent raising of sea levels worldwide. This rise provides a credible mechanism that could account for the ’sinking’ of Atlantis.
Mary Settegast, an archaeological researcher, has defended the early date for Atlantis with a remarkable book that delves extensively into Mediterranean and Middle Eastern prehistory and mythologies.
Immanuel Velikovsky (1895-1979) was by profession a doctor of medicine, specialising in psychiatry. However, his fame is based on being arguably the most controversial catastrophist of the 20th century. He daringly proposed that the Earth had a number of close encounters with other planetary bodies that resulted in catastrophic consequences, including interference with the rotation of our planet. He speculated that Atlantis was probably destroyed during one of these cataclysmic events.
Some have seen the influence of Ignatius Donnelly’s Ragnarok, written seventy years earlier, in Velikovsky’s cosmic collision theories. In fact a number of commentators have noted how Velikovsky seemed reluctant to credit earlier writers, such as W. C. Beaumont and Johann Radlof (1775-1846)(b), with their contributions to the development of the theory of planetary catastrophism. Rens Van Der Sluijs has written an interesting two-part paper(d)(e) listing the catastrophists who preceded Velikovsky demonstrating a certain lack of originality on his part! Others take a more critical view of his ideas(g). In 1950, he responded to this criticism with a defensive piece(n), but I consider it inadequate as he continued to ignore the work of Radlof and Beaumont.
Van Der Sluijs has written a two-part(k)(l) article on Velikovsky’s radical views regarding Venus as a comet-like body and how Aztec sources support some of his contentions.
Carl Sagan (1934-1996), was a well-known American astronomer, author and lecturer. He is considered a leading debunker of Velikovsky’s theories. He devoted much of his Broca’s Brain  to this end. Charles Ginenthal (1934-2017) produced an extensive rebuttal of Sagan’s criticisms in Carl Sagan & Immanuel Velikovsky .>However, criticism of Velikovsky continue with varying degrees of ferocity, such as that of Leroy Ellenberger, a former supporter of Velikovsky, who contends that the data from the Greenland ice cores fails to support Velikovsky(s).<
Velikovsky was initially inclined to link the disappearance of Atlantis with the eruption of Thera, but later came to support a location between the Azores and the Mid-Atlantic Ridge(i). He was an early questioner of Plato’s figure of 9,000 years for the age of Atlantis, suggesting that it was exaggerated by a factor of ten[0037.152]. ”Whatever the source of the error, the most probable date of the sinking of Atlantis would be in the middle of the second millennium, 900 years before Solon, when the earth twice suffered great catastrophes as a result of ‘the shifting of the heavenly bodies.’ These words of Plato received the least attention, though they deserved the greatest.”
Velikovsky offered intriguing evidence that on at least one occasion the early Egyptians experienced the sun rising in the west and setting in the east(q)! His other major contribution was in his questioning of the accepted Bronze Age chronologies of the eastern Mediterranean. Later writers, such as David Rohl and Peter James have built on his chronology work, while Gary Gilligan has added support for Velikovsky’s planetary theories as well.
One website(a) provides us with a considerable amount of Velikovsky’s unpublished work, while another offers an encyclopedia of his work(c). A more general German site(f), in English, is also worth a visit.
The three of Velikovsky’s most popular books as well as some of his lesser known papers are available as pdf files(j)(m).
Jan Sammer was an assistant to Velikovsky (1976-1978) and an archivist and editor for the Velikovsky Estate (1980-1983). He advises us that he was involved in the completion of Velikovsky’s unpublished book, In the Beginning, which can be read online(h).
In 2012, Laird Scranton, published The Velikovsky Heresies, in which he reviews Velikovsky’s controversial theories in the light of scientific discoveries since his death. Not unexpectedly, Scranton does find evidence that supports some of Velikovsky’s contentions.
Some readers may wish to see a video by Wallace Thornhill, of Electric Universe fame, in which he discusses Velikovsky’s Astrophysics (o). There are a number of free papers and books, including some Velivovskian material, available online(p).