The short bowler hat as we know it developed from a brutal murder in London in the 1860s. In the second half of the 19th century, bowlers were worn mostly by the working classes in Britain, with a crown that was much taller than the bowlers we’re used to now. More similar to the top hat, in fact. This 1877 photo from John Thomson shows the original height (the fellow on the right).
Chris Payne’s book Chieftain: Victorian True Crime Through the Eyes of a Scotland Yard Detective explains how the murder of Thomas Briggs in 1964 led to the development of the more compact bowler hat that we would recognize now. Briggs’s unconscious body was discovered on the trainline outside Hackney Wick, London. His head had been battered multiple times and his body thrown out of a moving train. Briggs later died in hospital.
The victim was known to wear one of the tall, bell-crowned hats pictured above. However, the hat was missing from the murder scene. Instead, there was a black beaver hat made for a smaller head. This turned out to be a vital clue. When the police eventually tracked down the suspect, Franz Mueller, they found a shorter-than-normal bowler hat in his possession. On further inspection, they found that Mueller had cut out a section to make it fit better, then repasted the felt to disguise the alteration. The case was covered extensively in the newspapers, and 50,000 people turned up to watch Mueller’s execution.
Payne reports that hatters cashed in on the huge publicity around the trial by producing cut-down bowler hats like the one below, which they called ‘Muller hats’. These shorter hats eventually become more popular than the original high-crowned affairs, until the taller bowlers disappeared entirely.
This murder case also contributed to East End slang, where the word ‘mullered’ meant ‘murdered’. This eventually came to mean ‘very drunk’ (e.g. I was mullered last night) and is still used in this sense.