DURING A WANDER through the rooms of Trerice House in Cornwall, which was constructed in the 15^th and 16^th centuries, we came across a 16^th century four-poster bed in one of the bedrooms. Unlike most four-poster beds, which can be seen in many National Trust properties, this one was missing its mattress. What could be seen is a rope threaded through holes drilled around the rectangular base of the bed. A long single rope was threaded through the holes so that a lattice of ropes formed a set of adjoining squares – a grid. The mattress would have been supported on the rope lattice. From time to time, the lattice would have become loose, -and the mattress would have sagged. The solution was to untie a knot at one end of the rope, and tighten the latticework before re-tying the rope.

My wife pointed out that this latticework arrangement resembled what is commonly seen in India: charpoys. A charpoy looks like a bed frame with four legs, but without a mattress. Ropes or strips of plastic are tied to the frame to produce a latticework very much like what we saw at Trerice. In India, charpoys are used to rest upon. Mattresses are not usually used.

A lady volunteer in the room at Trerice told us that the phrase “sleep tight” originated from the process of tightening the rope that supported mattresses on beds made long ago. This is the most common explanation of the expression. However, there is another (www.straightdope.com/21342710/what-s-the-origin-of-the-expression-sleep-tight), which is based on a definition in the Oxford English Dictionary:

“… what they say: ‘It seems that tight in this expression is the equivalent of the only surviving use of the adverb tightly meaning ‘soundly, properly, well, effectively.!’”

So, it is up to you to decide which of these two explanations sound most likely to you. Or, perhaps, you know of another.