September 2016 - This is an Etruscan bed-frame. Roman bed-frames were pretty much the same. It would have had a mattress on top of it, stuffed with feathers or straw, and wool blankets. This frame is made of bronze, so it has lasted and we can see it. But most Etruscan and Roman beds would have been made of wood and strung with wool or linen string. (We still make lawn chairs in about the same way that the Romans made beds.)
Many people probably didn't have mattresses. They slept right on the strings, or on straw mats laid on top of the strings. Cloth - because people had to spin and weave it by hand - was too expensive for most Roman people to use on bedsheets or mattress covers.
Learn by doing: try sleeping on a lawn chair laid flat, or in a hammock.
More about Roman houses
Ancient Rome (Eyewitness Books), by Simon James (2004).
Ancient Rome: A Guide to the Glory of Imperial Rome, by Jonathan Stroud (2000). A day as a time-travelling tourist in ancient Rome, for kids.
Houses, Villas, and Palaces in the Roman World, by Alexander McKay (1998).