The Dance/Ball of The Forty-One
In Good Omens, we see only a handful of flashbacks from Crowley and Aziraphale's past but two of them-- arguably, two of the most significant-- have something in common: the number 41.
There's the big one that we're being shown in multiple parts-- 1941-- but that is also taking place nineteen hundred years after the flashback set in the ancient Rome of 41 A.D.. The two also interconnect, with Part 2 of 1941 involving references between Crowley and Aziraphale to that night in ancient Rome.
So, why might Good Omens be repeating this number?
I think that this is a queer history reference to The Dance of The Forty-One-- also sometimes known as The Ball of The Forty One-- which was a Mexican society scandal in 1901. Basically, the police raided a private party in Mexico City that turned out to be a secret, queer, high society dance. They busted up a party that had a lot of men in drag and some sex workers in attendance and it was the height of scandal at the time. The police arrested 41 people at the party, which is how the scandal got its name in the press.
Many of the people at The Dance of The Forty-One, though, were very wealthy and very well-connected. They were more than willing to buy the silence of the police and press and did just that. While some names got out and some people were prosecuted, not everyone was. Of the 41 arrested, 12 wound up identified and went to prison but many others were able to buy their way to silence and a lack of jailtime.
It's thought that the press didn't manage to somehow get all of the information about who was at the party anyway because the government of Mexico wound up getting involved. Why did they? Because one of the attendees (and organizers lol) was apparently Ignacio de la Torre y Mier... the son-in-law of the then-President of Mexico.
The Dance/Ball of The Forty-One is thought by some to be the first time that queerness and existing queer community was openly discussed by most of the Mexican media, in large part because the nature of the story was so big that it couldn't be kept out of the normally pretty censored papers. There was plenty of the kind of hate that we might sadly expect. The group was often called (not just by the media but by people in general) "The 41 Maricones", a Spanish perjorative along the same lines of the English faggot.
This party is also responsible for a bit of one of Good Omens' favorite things-- etymology aka the history of words and their meanings. The Dance of The Forty-One is what led to the number 41 in Spanish-- cuarenta y uno-- becoming slang for a queer person across several Spanish-speaking countries.
So, on the very queer Good Omens, having some very significant years in the story contain the number 41 in a reference to The Dance of The Forty-One when this is the story of the secret romance of its queer main characters-- complete with them having a ball that goes a bit awry-- seems pretty fitting.
Other references to similar historical instances are already in Good Omens, like nods to the fate of Oscar Wilde and Aziraphale learning to gavotte in The Hundred Guineas Club, which had some ties to the eventual Cleveland Street scandal. Just as Crowley and Aziraphale have spent millennia dodging the supernatural police of their world, they've also been moving in queer circles on Earth where humans have been doing the same.
Additionally, there's a song that I don't think is being referenced here in Good Omens or anything but which goes along with this theme and is also very Crowley/Aziraphale. It's arguably the best song ever made by the Dave Matthews Band, and one which some have long interpreted as being something that is very Good Omens: a blasphemous love song queer-coded through use of etymology. Which song? The romantic pine fest 'mysteriously' 😉 entitled "#41".