Timaeus is the title of one of the two Dialogues of Plato, named after one of the participants. In it we encounter the first clear reference to Atlantis. The dialogue is usually seen as a continuation of The Republic. The first Latin translation of Timaeus comes from Cicero in the first century BC(b), but unfortunately from the point of view of Atlantology, he only translated 27d-47b, just missing the Atlantis passages. One of the most influential Latin translations came from Chalcidius in the 4th century AD. However, it fell to the 15th century Marsilio Ficino to produce the first translation of Plato’s complete works(c).
Some claim that Timaeus is the only character used by Plato that does not appear to have actually existed in ancient Greece. However, it is more generally accepted that the Timaeus in the Dialogues was based on a real astronomer and mathematician known as Timaeus of Locri, who was a Pythagorean philosopher who formed his own Pythagorean School in Locri in Southern Italy when the School in Croton was forced to close. Timaeus is said to have been around 70 at the time that the Dialogues were written.
Timaeus of Taormina who was born about 20 years before Plato died is not the Timaeus referred to in the dialogue of the same name. This Timaeus was a noted historian who among others was heavily relied on by Diodorus Siculus.
Also at issue is the actual authorship of Timaeus, because Hermippus of Smyrna (3rd cent. BC) claimed that Plato copied his text from the philosopher Philolaus. This suggestion has been debated into modern times(a).