Sexual identities are consciously changeable: one can begin life homosexual and choose to end up heterosexual.3 The area was greatly complicated by the work of Foucault, his followers and critics, who argued that linguistic categories common in the west such as sexuality, homosexuality and heterosexuality are no more than products of the modern western desire to put the experience of sex into words: other societies may have imagined matters very differently. The more recent emergence of gender studies has further complicated research into human sexual behaviour. Do apparently fundamental biological distinctions between men and women determine distinctive male and female behaviours? Or are masculinity and femininity also primarily constructed categories? It is this contentious context which provides the starting point for my research into the attitudes of tenth-century men towards sex.