Most philosophy, poetry, and literature discusses male-female relationships in terms of eros, romance, passion, sex, and marriage, rather than friendship. Friendship between males and females was acknowledged by some of the ancients, but almost exclusively as husband and wife. In Homer's Odyssey, Penelope had a role in extending xenia or guest friendship to various visitors to the family home in the absence of her husband, Odysseus. Her loyalty to Odysseus meant that this relationship got no closer. Lucius Annaeus Seneca (c. 4 B.C.E.–65 C.E.) and Plutarch (c. 46–after 119 C.E.) both write about the importance of friendship between husband and wife. The only philosopher of antiquity to consider women and men as equally capable of engaging in friendship was Epicurus (341–270 B.C.E.), whose Garden of Friends was open to all—men, women, and slaves.
Courtly love of the Middle Ages and the idealized relationships of the Romantic era emphasized not equal affectionate friendships, but unattainable, idealized, and exclusive male-female intimacy. It was the movement for women's equality that transformed relationships for women, both with men and with other women. The personal and political were combined in, for example, the friendships of one of the first feminists, Mary Wollstonecraft (1759–1797), during the French revolution with dissenters such as Richard Price (1723–1791) and Joseph Priestly (1733–1803), or in the bohemian literary and art circles of the early twentieth century, as with the New Zealand writer Katherine Mansfield and the Scottish painter J. D. Ferguson. Women's participation in the civil rights and the antiwar movements in the 1960s brought men and women together as friends fighting political battles. However, the concurrent sexual revolution, which endeavored to free women from the restraints of Victorian attitudes, focused on uninhibited carnal relationships rather than nonsexual friendships. The literature of heterosexual relationships became dominated by the field of psychology and includes warnings to women to avoid "love addiction" or advice about sexual enjoyment.