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Though I’ve covered a lot in my time at the helm of Slate’s crime blog, I haven’t yet delved into crimes against fashion. I’m not talking about wearing white tube socks with a business suit, although people who do that certainly merit the harshest punishments imaginable. No, I’m here to discuss those times when violent gangs of hoodlums take to the streets in great numbers, viciously attacking all those whose apparel is out of season. I’m talking about the Straw Hat Riot of 1922.

There’s nothing particularly old-fashioned about violent youth gangs tearing through city streets, assaulting hapless passerby—it happened just last weekend in Chicago. But it has been a very long time since those gangs were motivated by an intense dislike of the straw boater hats favored by garden party attendees and members of barbershop quartets. Back in the day before hooded sweatshirts were deemed acceptable boardroom attire and men’s brimmed hats were worn exclusively by swing-dance revivalists and nerds with neckbeards, hat fashion was serious business—and it hewed to a rigorous seasonal etiquette. The most important rule: absolutely no straw hats after September 15. If you ignored that deadline, then your hat was fair game for any urchin who wanted to snatch it off your head and stomp it to pieces.

Nobody’s quite sure why September 15 became the straw-hat cutoff date, rather than, say, Labor Day (the symbolic end of summer) or September 21 (the actual end of summer). But the basic idea, I think, was that straw hats were warm-weather apparel, and wearing them during autumn’s approach marked you as a rube and a boor. Since rubes and boors don’t know better than to take off their summer hats once autumn starts, hooligan children across America took it upon themselves to perform that service for them.

Some hat-snatchings were more violent than others. A Pittsburgh Press article from Sept. 15, 1910 described an incident in which “the police had to interfere in more than one instance to protect straw-lidded pedestrians.” While chalking the riots up to the exuberance of youth, the Press foresaw dangerous consequences if things were taken too far: “It is all right for stock brokers on the exchanges to destroy one another’s hats if they like, on the principle that everything goes among friends. But no man likes to have his hat snatched from his head by somebody he has not yet been introduced to.”

The truth of that observation was borne out in New York City in 1922, when a hat-snatching turned into a full-fledged, days-long riot. It began when a few kids in Manhattan’s “Mulberry Bend” section decided to disregard the traditional September 15 deadline and start snatching hats early, on September 13. They targeted some dockworkers; the dockworkers got angry and began to fight back. One thing led to another, and soon enough large hat-hating gangs were roaming through the city, snatching hats and attacking people en masse, occasionally using clubs studded with sharp nails.

The night of September 13 was a violent one. “Straw Hat Riots Embroil East Side,” reported the New York Times of Sept. 14, 1922, asserting that “the inalienable right of a man to wear a straw hat in a snowstorm, if he desires, is to be upheld in this city by both police and the Magistrates, and a warning was sent broadcast to all straw hat smashers last night that jail terms on assault charges awaited them if they started any such carnival today.”

But the riots continued the next day, and the day after that, moving from the East Side to the Upper West Side, where Amsterdam Avenue was reportedly packed with straw hat partisans. “In some cases, mobs of hundreds of boys and young men terrorized whole blocks,” reported one article. “Complaints poured in upon the police from men whose hats were stolen and destroyed. But as soon as the police broke up the gangs in one district, the hoodlums resumed their activities elsewhere.” Not even police were exempt from the danger: “One police sergeant was tripped and fell into a gutter while chasing boys who had battered his hat,” the Associated Press reported on September 16.

By then, though, the riots had calmed down. In the end, nobody was killed, although many people were wounded, and two valuable lessons were learned: 1) seriously, do not wear a straw hat after September 15; and 2) New Yorkers are crazy and will riot at the slightest provocation. The next few Septembers saw more incidents of hat-related violence, though nothing on the scale of the 1922 riots. Eventually, fashion standards relaxed, America got depressed, and hat-related roughhousing no longer seemed so important. But we’ll always have the memories.