Proleptic Gregorian calendar Proleptic Gregorian calendar The proleptic Gregorian calendar is produced by extending the Gregorian calendar backward to dates preceding its official introduction in 1582. In countries that adopted the Gregorian calendar later, dates occurring in the interim (between 1582 and the local adoption) are sometimes "Gregorianized" as well. For example, George Washington was born on February 11, 1731 (Old Style), as Great Britain and its possessions were using the Julian calendar with English years starting on March 25 until September 1752. After the switch, that day became February 22, 1732, which is the date commonly given as Washington's birthday. The proleptic
Adoption of the Gregorian calendar fourth great beast of Daniel, led the Queen to let the matter be quietly dropped. In the , Protestants resisted the calendar imposed by the Habsburg Monarchy. In parts of Ireland, Catholic rebels until their defeat in the Nine Years' War kept the "new" Easter in defiance of the English-loyal authorities; later, Catholics practising in secret petitioned the Propaganda Fide for dispensation from observing the new calendar, as it signalled their disloyalty. The Lutheran Duchy of Prussia, until 1657 still a fiefdom of Roman Catholic Poland, was the first Protestant nation to adopt the Gregorian calendar. Under influence of its