Diogenes Laertius Life of Thales the Philosopher 1. 1. 11 :

According to Demeterius of Magnesia in his Men of the Same Name, there have been five others of this name, of whom . . . the third belongs to very ancient times, namely those of Hesiod, Homer, and Lycurgus.26

Plutarch Life of Lycurgus 4 :

One of the men who had a name in Crete for wisdom and statesmanship Lycurgus prevailed on by favour and friendship to go to Sparta. This was Thales, who was ostensibly a composer of songs for the lyre but did the work of a lawgiver of the best sort. For his songs were exhortations to lawabidingness and concord made by means of melodies and rhythms themselves marked by order and tranquillity.

Ephorus quoted by Strabo Geography 10. 48 :

[on the Cretans]: Similarly the rhythms they use in their songs are Cretan, the grave and severe rhythms invented by Thales, to whom moreover they ascribe the Paeans and other native songs as well as many of their customs.

Pausanias Description of Greece 1. 14. 4 :

Thales who stayed the plague at Sparta . . . was a native of Gortyn according to Polymnastus of Colophon, who composed some epic lines on him for the Spartans.

Aelian Historical Miscellanies 12. 50 :

The Spartans, who bent was for bodily exercises and feats of arms, had no skill in music. Yet if ever they required the aid o the Muses on occasion of general sickness of body or mind or any like public affliction, their custom was to send for foreigners, at the bidding of the Delphic oracle, to act as healers and purifiers. For instance they summoned Terpander, Thales, Tyrtaeus, Nymphaeus of Cydonia, and Alcman.

Plutarch On Music 9 :

The first establishment of music at Sparta was due to Terpander. The second is best ascribed to Thaletas of Gortyn, Xenodamus . . ., Xenocritus . . ., Polymnastus . . ., and Sacadas. For we are told that the Feast of Naked Youths at Sparta27 . . . was due to these musicians . . . Thaletas, Xenodamus, and Xenocritus were composers of Paeans.

Ibid. 42 :

Many circumstances could be citied to show that good music has been a matter of concern to the best-regulated states, and not least among these the quelling of a rising at Sparta by Terpander . . . And according to Pratinas, Thaletas the Cretan who is said to have been invited thither at the instance of the Delphic oracle to heal the Spartans by his music, rid their city of the plague which ravaged it.

Ibid. 10 :

As for Thaletas of Crete, it is doubted whether he composed Paeans. Glaucus, who puts him later than Archilochus, declares that he imitated that poet with the difference that his songs were longer and he employed the Paeonic and Cretic rhythms. These had not been used by Archilochus, nor indeed by Orpheus or Terpander, but are said to have been derived by Thaletas, who thus showed himself a great poet, from the flute-music of Olympus.

Porphyrius Life of Pythagoras :

He used to amuse himself alone in his own house of a morning by singing certain ancient paeans of Thales to his own accompaniment on the lyre.

See also Plut. Ag. 10, Princ. Phil. 4, Strab. 10. 482, Philod. Mus. xix.

26. cf. Strabo 10. 482
27. cf. Ath. 15. 678b