Three-Threads was a beer drunk in early 18th- century London and is commonly considered to have been a mixture of three types of beer drawn from separate casks in the ale house. The name survives as the cornerstone of an enduring tale concerning the origins of porter. According to the tale, porter was invented in “around 1722” when a brewer succeeded in duplicating three-threads in a single cask for the convenience of the publican. This account, which first appeared in 1760, has been repeated many times in the popular literature, frequently without attribution and sometimes with elaboration. It has been refuted, if not laid to rest, by modern scholarship, which asserts that porter was an existing brown beer that came to be produced on a massive scale by the great London brewers from the 1720s. The scale of production, changes in ingredients, and increased storage time led to changes in the beer’s flavor, but there was no single “invention” of porter as such. Three-threads did exist; it is referred to in a “good pub guide” for London published c. 1718, but it apparently had nothing to do with porter. Although most commonly given as a mixture of pale ale, mild (fresh brown beer), and stale (matured brown beer), there is no definitive information on the combination of beers that went into three-threads. It has even been hypothesized from limited and somewhat ambiguous contemporary evidence that three-threads was not drawn from three separate casks by the barman, but rather was supplied ready blended by the brewery. Therefore, sadly, it seems that we cannot truly know anything for certain about the beer called three-threads other than its name.