The original source for the claim that she was Socrates' wife appears to have been a work by Aristotle called On Being Well-Born,^[1][2][3] although Plutarch expresses doubt that the work is genuine. She was apparently the daughter,^[3] or, more probably, the granddaughter of Aristides.^[2] A different account of Xanthippe and Myrto is given in Aristoxenus's Life of Socrates written in the latter part of the fourth century BC that Aristoxenus asserts is based on first-person accounts by his father. This claims that Myrto was his legitimate wife and Xanthippe his mistress, whose child became legitimate.^[4]

Although Diogenes Laërtius describes Myrto as Socrates' second wife living alongside Xanthippe, Myrto was presumably a common-law wife,^[5] and Plutarch describes Myrto as merely living "together with the sage Socrates, who had another woman but took up this one as she remained a widow due to her poverty and lacked the necessities of life."^[2] Athenaeus and Diogenes Laërtius report that Hieronymus of Rhodes attempted to confirm the story by pointing to a temporary decree the Athenians passed:

For they say that the Athenians were short of men and, wishing to increase the population, passed a decree permitting a citizen to marry one Athenian woman and have children by another; and that Socrates accordingly did so.

— Diogenes Laërtius, ii. 26

Neither Plato nor Xenophon mention Myrto, and not everyone in ancient times believed the story: according to Athenaeus, Panaetius "refuted those who talk about the wives of Socrates."^[1]