Lambert described Antinous as "the one person who seems to have connected most profoundly with Hadrian" throughout the latter's life. Hadrian's marriage to Sabina was unhappy, and there is no reliable evidence that he ever expressed a sexual attraction for women, in contrast to much reliable early evidence that he was sexually attracted to boys and young men. For centuries, sexual relations between a man and a boy had been socially acceptable among Greece's leisured and citizen classes, with an older "erastes" (the "lover", aged between 20 and 40) undertaking a caring sexual relationship with an "eromenos" (the "beloved", aged between 12 and 18) and taking a key role in his (the latter's) education. Hadrian took Antinous as a favoured servant when they were aged about 48 and 13 respectively. Such a societal institution of pederasty was not indigenous to Roman culture, although bisexuality was widely socially accepted in the upper echelons of Roman society by the early 2nd century.