Thales son of Herakleides, together with Aderitos son of Thersandros and Demetrios son of Artemon, is a man mentioned in a list of theoroi (I.Samothrace Theoroi 6, 23) who paid an official visit to the shrine of the Great Gods in Samothrace, during the same unknown year. The eponymous basileus of this year in Samothrace is [—]x son of Athana[—], not attested elsewhere.

The origin of this group of three theoroi was correctly restored as Samos by L. Robert (Robert 1935, pp. 487-488). The other delegations of theoroi came from Cos and Teos. All these men were rewarded with proxeny.

To date I.Samothrace Theoroi 6 one has to rely mainly on palaeography: the shape especially of deltas, ni, omicron, and pi suggests that the text was inscribed in the mid-to-late Hellenistic period.

While the patronymic Herakleides is extremely wirdespread, Thales is not a very common name, even in a Ionian city like Samos. A list of winners in different competions mentions a gymnasiarch whose name is Thales son of Euelthon, natural son of Herak[leides] (IG XII 6, 179 l. 1). This list dates back to the begininng of the 2nd c. BC. Even if the the name of the natural father is not entirely preserved, another element to consider is that one of the winner (l. 6) bears the same name of one of the colleagues of Thales, Demetrios son Artemon. It is therefore possible that the two, although of different ages, were part of the same embassy sent to Samothrace at a time after the competitions.

If this reconstruction is true, a Thales son of Euelthon of a later time (IG XII 6, 289; possibly also in IG XII 6, 225 l. 5) could be the grandson of this man.