There is an Irish tradition that names Murias as one of the four cities of the Tuatha dé Danaan(b), who came to Ireland a thousand years before the Celts.
The pre-Hellenic Greeks were known as the Danai and were, according to an Egyptian source, the descendants of Danaus. Furthermore, the Danai have been linked with the legendary Tuatha dé Danaan of Ireland as well as the Shardana of Sardinia.
(a) Atlantis, A New Concept. Pt.1, Atlantis May-June, 1974
Achaean is a term that has been applied in a variety a ways over the past 4,000 years to identify different groups and geographical areas. Originally it described the first of the Greek-speaking peoples who arrived on mainland Greece around 2000 BC. Homer also referred to them as Achaioi as well as Argives and Danai (Strabo 8.6.5). Achaioi was probably the Anatolian name for them. Argives refers to the inhabitants of Argos and the Danai were the descendants of the Egyptian Danus who moved to Argos. Homer used Danai as a general term applied to all Greeks. Similarly, it quite possible that Atlantis and the individual members of their alliance had each been known by a number of different names.
The Achaeans were the founders of the city of Mycenae, in the North-Eastern Peloponnese, which gave its name to the Mycenaean civilisation of Late Bronze Age Greece (1700-1200 BC). There is no consensus regarding their origin. There is some agreement that the Hittites knew them as Ahhiyawa. Rodney Castleden expands on this idea in his Mycenaeans. Helike, one of their cities, was destroyed in 373 BC, by inundation following an earthquake in a similar manner to the destruction of Atlantis as described by Plato.*Iain Stewart also supports Helike, the former capital of the Achaean League, as the most likely inspiration for Plato’s Atlantis story(b).*
Today Achaea is the name of an administrative area of Greece.
Some writers such as Jürgen Spanuth and more recently Felice Vinci have argued strongly in favour of the controversial theory that the Achaeans were a Baltic tribe that migrated south. Iman Wilkens maintains that ‘Achaean’ means ‘watermen’ or ‘Sea People’(a), which has other obvious implications.