Because the nature of male-male and male-female relationships in Ancient Greece differ greatly from our own, it is useful to discuss how the society that Socrates and Plato thought about these topics in a consideration of Lysis. First, the modern term “homosexual” and is not appropriate to this discussion. Homosexuality, as we understand it, is the product of a post-Freudian, industrialized world, where sexuality has been interpreted as a structural and constitutive feature of personality. The word suggests not just a sexual practice, but also the notion that one’s sexual preference in some way defines one’s character. 

In Ancient Greece, most men would marry women and produce children with them, but many would have male lovers as well, with whom there was often a closer emotional bond. But just as “homosexual” is an inappropriate category, so is “bisexual,” as it suggests a middle ground between homosexuality and heterosexuality. All we can rightly say is that most men in Ancient Greece would engage in sexual relationships with both men and women, and that some had a stronger preference for men and some had a stronger preference for women. There is some evidence to suggest that male-male relationships were more prevalent and more valued in the intellectual circles that Plato writes of than among the people of Athens at large.

Typically, a male-male relationship would exist between an older man (called the "lover") and a younger man (called the "loved one" or "boyfriend"). The older man takes the initiative in the relationship and is usually the dominant partner in sexual intercourse. The younger man, usually in the age between puberty and that of growing a beard, would gain in return the help, favor, and mentorship of the older man. The lover is often married to a woman at the time, and life-long partnerships, such as the one that exists between Agathon and Pausanias, are rare. 

While many men preferred women, both as sexual partners and as wives, male-male relationships were idealized for several reasons. The activities the Greeks believed most powerfully displayed virtue and glory—including athletics, philosophy, warfare, rhetoric—were exclusively the realm of men at the time, so two men could share in this virtue and glory in a way that a man and a woman could not. Women in ancient Greece were obviously equally capable of rational development as women today, but they were not, for the most part, provided with the opportunities to prove this. The male and female spheres in Ancient Greece were very rigidly separated, so there was not much common ground for romanticized courtship between men and women. Marriage was often a social necessity in order to ensure reproduction, while male-male love was considered purer because it was less practical.

Additional Historicial Context for Lysis

While there isn't a great deal of historical context necessary to the understanding of Lysis except to have a general understanding of how relationships between men and boys often functioned in Athenian life at the time as described above, it is sometimes helpful to recall that the Athens in which Plato wrote the Socratic dialogues was not a static, ideal state. Plato was writing about philosophical ideals, but his specific concerns and examples are often shaped by an awareness of the national and international power struggles that helped shape Athenian society. The same can be said of Socrates, whose major targets (according to Plato) often included the inflated traditional ideals of the ruling aristocracy. The Greek code of virtue and honor, based strongly in oral history (poetry) and religion, was generally seen as self-evident. It had certainly never been subjected to the kind of relentless analysis that Socrates developed.

Both Socrates and Plato criticized and re-invented Athenian systems of value, and both ran into real-world trouble with the judicial and governmental structures in which those values were embodied (Plato in his early career in politics, Socrates at the end of his life). Lysis is an intriguing instance of Plato working carefully, through Socrates, at one of the very centers of Athenian social life.