I read once that style of biphasic sleeping used to be really common before electricity. People would go to sleep pretty much with the sun, wake for a few hours in the middle of the night. Husbands and wives would have time with each other before falling back asleep and then waking with the sun.
Discussion
The religious used to pray in the middle of the night while awake. The nightike prayer was called Matins and was said around 2AM.
I was trying to abbreviate what people did while awake. I realize now I made it sound like they were having sex. The article went into examples of activities across classes and sleeping arrangements.
