Comment by masklinn

> It’s actually worse than that. It wasn’t always whole coubtries who decided to adopt (or not) but cities and sometimes people within cities (i.e. the protestants in the city would be lagging, or maybe I’m misremembering and this was about people who where abroad)

There was some of that indeed, depending on the centralization of the country e.g. Spain and France adopted the gregorian calendar wholesale because the king decreed it, but in less centralised countries like the Dutch Republic or Switzerland it happened by region (the seven catholic cantons switched to the gregorian calendar in 1584, the protestant canton only switched over piece by piece during the 18th century, and Schiers and Grüsch were the last remnants of Julian calendar in the entirety of western europe, only adopting the gregorian calendar in 1812).

... and then there's Sweden, which started on a plan to gradually approach the Gregorian calendar by skipping leap years over 40 years, except they immediately forgot to skip the second and third so concluded the plan was stupid, then instead of switching to gregorian they reverted to julian, before finally switching to gregorian 40 years after that.