Simonides, however, says that the sail given by Aegeus was not white, but ‘a scarlet sail dyed with the tender flower of luxuriant holm-oak,’ and that he made this a token of their safety. Moreover, the pilot of the ship was Phereclus, son of Amarsyas, as Simonides says (original Greek).
DS (Diodoros Siculus) 4.61.4 and 4.61.6-7:
Now Theseus was one of those who were to set forth, and Aegeus made the agreement with the captain of the vessel that, if Theseus should overcome the Minotaur, they should sail back with their sails white, but if he died, they should be black, just as they had been accustomed to do on the previous occasion…
But Theseus, they say, being vexed exceedingly because the maiden had been taken from him, and forgetting because of his grief the command of Aegeus, came to port in Attica with the black sails.
And Aegeus, we are told, witnessing the return of the sip and thinking that his son was dead, performed an act which was at the same time heroic and a calamity; for he ascended the acropolis and then, because he was disgusted with life by reason of his excessive grief, cast himself down the height (original Greek).
There is but one entry to the Acropolis… On the right of the gateway is a temple of Wingless Victory. From this point the sea is visible, and here it was that, according to legend, Aegeus threw him self down to his death (original Greek).
Plutarch, Theseus 22.1:
It is said, moreover, that as they drew nigh the coast of Attica, Theseus himself forgot, and his pilot forgot, such was their joy and exultation, to hoist the sail which was to have been the token of their safety to Aegeus, who therefore, in despair, threw himself down from the rock and was dashed in pieces (original Greek).
ApE (Apollodoros, Epitome) 1.10:
In his grief on account of Ariadne, Theseus forgot to spread white sails on his ship when he stood for port; and Aegeus, seeing from the acropolis the ship with a black sail, supposed that Theseus had perished; so he cast himself down and died (original Greek).
When Theseus left [the island of Dia], he forgot to change the black sails, and so his father Aegeus judged that he had been devoured by the Minotaur. He threw himself into the sea, which was called Aegean from this (original Latin).
Aegeus, son of Neptune, threw himself into the sea, and the Aegean Sea is called from this (original Latin).
∑ Aen (Servius Grammaticus, Commentary on the Aeneid of Vergil, ed. G. Thilo and H. Hagen, 1881) 3.74.
It is better to take him [Homer] as meaning the Aegae in Euboea, from which it is probable that also the Aegean Sea got its name (original Greek).
Hipp (Euripides, Hippolytos) 34-35:
Theseus has left the land of Cecrops,  fleeing the blood-guilt he incurred for the murder of the Pallantidae (original Greek).
Edited by Frances Van Keuren, Prof. Emerita, Lamar Dodd School of Art, Univ. of Georgia, July 2016.