What Does Sleep Like a Log Mean?

Similes are as old as the hills – they’re like a foundation upon which much of literature is built. As such, the more obvious of similes go back some way. Often, they crossed national boundaries with the populations of migrants and soldiers that ebbed and flowed over Europe for much of history. It was therefore surprising that most online etymological discussions around the phrase “sleep like a log”, and Ngram data goes back only to around the early 19^th century.

With a little more research, however, you can follow it back to a couple of documented examples in the mid-16^th century in Spanish, and mid-17^th century in English. For example, the Spanish occurrence is in a poem called Cancionero llamado Sarao de amor (songbook called [untranslatable] of love) by Juan de Timoneda (1561) which reads:

While not proof that the phrase would have made it into the English language at the exact time, documented idioms tend to have been present colloquially for some time. And considering Philip II of Spain was briefly the King of England from 1554 to 1558 – there was plenty of cross-cultural interaction in the form of various wars, so it’s likely that language travelled across the same borders. However, despite this early connection between Spain and England, more recent history shows the phrase entering American publications more so than their British counterparts.

The first example was found in a collection of newspaper anecdotes cited in the Boston Transcript of 1830, while the second comes from The Life and Adventures of Dr Dodimus Duckworth, published in New York in 1833. More examples can also be found of this phrase in American texts of a similar time. It’s therefore fair to assume that this prevalence of usage in American publications suggests the phrase was most well established across the Atlantic.

That said, it was clearly also in usage in British texts too around a similar time too – just less frequently. One of the earliest examples we can find in a British text is in an article for the Gloucestershire Chronicle on the 12th of April 1834, as presented by The British Newspaper Archive:

Despite the fact usage of this phrase really started to gain momentum around the early 19th century in English speaking countries, it is still reasonable to assume it entered into common use in English around the end of the 16^th and maybe as late as the early 17^th Century. The prevalence of similar phrases appearing in other European languages at this time creates a strong argument that the origin goes back at least this far and perhaps somewhat further.