Problems with the Adoption
Gregory's Inter Gravissimas commanded all Christians to abolish the old methods and adopt his new provisions. The Bull also allowed for some difficulties, ordering distant areas to change in whichever year the news reached them. However, the European switch from Old Style to New Style was complicated by much more than geographic extent.
Early Adopters
The Pope is head of the Catholic Church, and has no authority over Protestants; indeed, in the 16th century many were actively opposed to 'Popery'. Of the countries that immediately adopted Gregory's reforms all were officially Catholic. Italy, Poland and Portugal followed the Bull precisely, moving straight from the 4th to the 15th of October, while France, Belgium, Luxembourg and parts of the Netherlands and Switzerland converted later in the year. By 1585 many of the Catholic regions in Germany, Austria and the Czech/Slovak territories had also adopted the Gregorian calendar; Hungary followed in 1587. Conversely, the Protestant nations kept the Julian calendar, causing a division that lasted for over a century, while the Eastern Orthodox Church also rejected the New Style.Aside from Prussia, which moved from the 22nd August to the 2nd September in 1610, the next round of changes occurred during 1700/01, when Denmark (which then included Norway) and the remainder of Germany, Switzerland and the Netherlands became Gregorian. (One Swiss canton, St. Gallen, held out until 1724). However, these Protestant states continued to reject Gregory's rules for the determination of Easter until 1776. The next nation to convert was Britain in 1752, at which point another full Julian cycle had elapsed requiring the omission of an extra eleventh day: the 2nd September was followed by the 14th. This date also saw the calendar adopted throughout the British Empire: the lands later known as the USA had now become Gregorian. Sweden changed a year later, in 1753.
Further Religious Differences
At this point in history the Gregorian Calendar was still a Christian device, prompted by, and designed around, religious festivals. While western Europe was predominantly Christian, and now Gregorian, large parts of central and eastern Europe were under Muslim rule. Consequently, these countries had no intention, or over-riding religious need, to change. Although the Gregorian calendar slowly spread across the world during the 18th and 19th centuries, the situation in Europe remained static until 1912.
Later Adoptions
As the Ottoman Empire slowly collapsed several countries followed their independence with a switch to the Gregorian calendar, including Albania in 1912. However, the process that finally united the calendars of Europe was ignited by the 1st World War. Some countries were forced into accepting the reforms by an occupying army - these included Latvia and Lithuania - while others, notably Russia, switched in the aftermath of a revolution. The post-war division of the Ottoman Empire led to many of the Baltic countries adopting the Gregorian calendar, and Turkey itself followed at the end of 1926. Additionally, while the Eastern Orthodox Church has never fully accepted the calendar, it did introduce several changes during 1923 that brought them closer together.
Confusion over Dates
These were the years when each country officially adopted the Gregorian Calendar; in practice, many people within each state continued to use the Old Style for long after this. Some Protestants remained opposed to the reforms, but large numbers of people simply preferred the Julian method, which was too long-standing and ingrained for them to change. Unfortunately, there is no definitive list of the dates when each country changed. Although many of the adoptions are well recorded, such as those of France and Italy, the situation in some countries is more confused. In theory, a trawl through each nation's legislation would reveal the results, but the changing geography and political identities within Europe makes this a large task. Consequently, online charts and lists will normally give several possible dates for several countries, which include Bulgaria and Scotland.
