A romantic friendship, passionate friendship, or affectionate friendship is a very close but typically non-sexual relationship between friends, often involving a degree of physical closeness beyond that which is common in contemporary Western societies. It may include, for example, holding hands, cuddling, hugging, kissing, giving massages, or sharing a bed, without sexual intercourse or other sexual expression. The term is typically used in historical scholarship, and describes a very close relationship between people of the same sex during a period of history when there was not a social category of homosexuality as there is today. In this regard, the term was coined in the later 20th century in order to retrospectively describe a type of relationship which until the mid-19th century had been considered unremarkable but since the second half of the 19th century had become rarer as physical intimacy between non-sexual partners came to be regarded with anxiety. Romantic friendship between women in Europe and North America became especially prevalent in the late 18th and early 19th centuries, with the simultaneous emergence of female education and a new rhetoric of sexual difference. Historical examples The study of historical romantic friendship is difficult because the primary source material consists of writing about love relationships, which typically took the form of love letters, poems, or philosophical essays rather than objective studies. Most of these do not explicitly state the sexual or nonsexual nature of relationships; the fact that homosexuality was taboo in Western European cultures at the time means that some sexual relationships may be hidden, but at the same time the rareness of romantic friendship in modern times means that references to nonsexual relationships may be misinterpreted, as alleged by Faderman, Coontz, Anthony Rotundo, Douglas Bush, and others. Shakespeare and Fair Youth The content of Shakespeare's works has raised the question of whether he may have been bisexual. Although 26 of Shakespeare's sonnets are love poems addressed to a married woman (the "Dark Lady"), 126 are addressed to an adolescent boy (known as the "Fair Youth"). The tone of the latter group, which focuses on the boy's beauty, has been interpreted as evidence for Shakespeare's bisexuality, although others interpret them as referring to intense friendship or fatherly affection, not sexual love. Among those of the latter interpretation, in the preface to his 1961 Pelican edition, Douglas Bush writes: Bush cites Montaigne, who distinguished male friendships from "that other, licentious Greek