There are a large of figures in history that have been known to have had sexual relations with members of the same sex, and are (more recently) suspected or argued to have been gay. There's a problem with this that inevitably occurs in the latter judgement—one that requires a presentist judgement on sexual orientation of figures that would not have fit into those categories as we see them today. The idea of a 'gay' identity doesn't really emerge in western societies until the turn of the twentieth century, with works like George Chauncey's Gay New York: Gender, Urban Culture, and the Making of the Gay Male World 1890-1940 argues that sexuality had up until that period been largely defined by gender, in that it was seen that a male taking the penetrative role would not have suffered any sense of masculinity, while the other would be seen as effeminate or 'wanting' to be feminine. It's only with the progression of the early decades of the twentieth century that this idea of sexual inversion starts to get supplanted by orientation as we tend to think of it. John D'Emilio in "Capitalism and the Gay Identity" takes a different but not irreconcilable view, arguing that the interaction between capitalism (and its becoming the dominant economic order) and the family unit allowed individuals to break free from the traditional order that saw sexuality as a means to procreation, and instead began to realize their freedom to explore their interest in the same sex, and begin to identify according to sexuality. Richard Godbeer in Sexual Revolution in Early America also touches on this issue, noting (taking a summary from /u/smileyman) that individuals did not think of sexuality in terms of attraction to male or female until fairly recently, and certainly not in colonial or revolutionary America.