Was Abraham Lincoln gay? A new documentary, “Lover of Men,” explores the question.

The 2012 book, “The Stories Soldiers Wouldn’t Tell: Sex in the Civil War,” by Thomas P. Lowry, looks at this and many other questions of sexuality during that period. From this distance, it’s hard to figure out what was going on — very few people were writing candidly about that kind of thing in the 19th Century, and 21st Century attitudes and definitions toward sexuality and gender don’t map well onto the past.

Men often shared beds back then; this is common knowledge. In a highly sexist society, they formed intense friendships. There was probably a lot of sex going on between men.