"... just like more than 300 years went by before the last Protestant nation implemented Greg's proposal ..."
This is not correct. The last Protestant nation that adopted the Gregorian calendar was Sweden. The adoption was stepwise (including some oddities) and was complete in 1753 (less than 200 years). The Swiss canton of Grissons (which was half Protestant and half Catholic) adopted it in 1811. It was the Orthodox countries that took more than 300 years to adopt it. The last one was Greece in 1923.
Ever wondered why Calendar components in Microsoft's WinForms framework does not go further back then 1753? -- It was the first year when the British Empire fully used the Gregorian calendar (the transition was in 1752). Protestant software ...
Technically the Serbian Orthodox Church still hasn't adopted the Gregorian calendar, so their religious holidays continue to gradually fall further out of sync with the rest of the world. Eventually they'll have Christmas in July.
I didn't want to make things too complicated, so I focused on the adoption by nation states in my original post. The use of the Julian calendar in todays Serbian Orthodox Church you mentioned is a special of a broader movement. Some other Orthodox Churches use it as well. In a sense, the only territory that AFAIK uses the Julian calendar today is the Monastic Republic of Mount Athos[1], which is an autonomous self-governed territory inside Greece.
This is not correct. The last Protestant nation that adopted the Gregorian calendar was Sweden. The adoption was stepwise (including some oddities) and was complete in 1753 (less than 200 years). The Swiss canton of Grissons (which was half Protestant and half Catholic) adopted it in 1811. It was the Orthodox countries that took more than 300 years to adopt it. The last one was Greece in 1923.
Ever wondered why Calendar components in Microsoft's WinForms framework does not go further back then 1753? -- It was the first year when the British Empire fully used the Gregorian calendar (the transition was in 1752). Protestant software ...