I spent some time yesterday reading articled about sleep, to make insomnia less boring. One thing I encountered was this: Segmented Sleep which cites The Myth of the Eight Hour Sleep
Some historians have studied how sleep is mentioned in old texts, and found that it was probably common before the 1900s to sleep twice in one night. The dark period would be longer because of less artificial light, so people would go to sleep when it got dark, wake up after about 5 hours, stay awake for a short while and fall asleep again.
The article argues that this kind of sleep schedule is likely to concentrate deep sleep in the first sleep period, and REM sleep in the second. The wakeful perior in between is said to be very peaceful and good for creativity. This sounds very familiar for a WBTB practitioner. Could it be that this is what everybody used to do, and that it has just disappeared from our cultural memory?
The study has only included European texts. It would be very interesting to read what people on other continents wrote about sleep before the industrial revolution. I am actually tempted to try out this schedule for a while to see if it can improve sleep quality and dream recall.