Lesbian literature is a subgenre of literature addressing lesbian themes. It includes poetry, plays, fiction addressing lesbian characters, and non-fiction about lesbian-interest topics. Fiction that falls into this category may be of any genre, such as historical fiction, science fiction, fantasy, horror, and romance. List of lesbian periodicals in the United States Lesbian literature includes works by lesbian authors, as well as lesbian-themed works by heterosexual authors. Even works by lesbian writers that do not deal with lesbian themes are still often considered lesbian literature. Works by heterosexual writers which treat lesbian themes only in passing, on the other hand, are not often regarded as lesbian literature. The fundamental work of lesbian literature is the poetry of Sappho of Lesbos. From various ancient writings, historians have gathered that a group of young women were left in Sappho's charge for their instruction or cultural edification. Not much of Sappho's poetry remains, but that which does demonstrates the topics she wrote about: women's daily lives, their relationships, and rituals. She focused on the beauty of women and proclaimed her love for girls. Certain works have established historical or artistic importance, and the world of lesbian fiction continues to grow and change as time goes on. Until recently, contemporary lesbian literature has been centered around several small, exclusively lesbian presses, as well as online fandoms. However, since the new millennium began, many lesbian presses have branched out to include the works of trans men and women, gay and bisexual voices, and other queer works not represented by the mainstream press. Additionally, novels with lesbian themes and characters have become more accepted in mainstream publishing. The European Middle Ages lacked a specific term for lesbians, but medieval French texts, under the influence of the Arabic literature of the period, featured literary depictions of love and sexual desire between women.