Illustration of two people talking in a village at night

Illustration of the traditional French song “Au clair de la Lune,” by illustrators Maud and Miska Petersham, from Nursery Friends from France, 1925. Before the Industrial Revolution and the invention of mechanical clocks, it was common to split sleep into two parts. In France, the wakeful period between was known by the portmanteau dorveille.

The Protected Art Archive/Alamy Stock Photo