Year 1712 (MDCCXII) was a leap year starting on Friday (link will display the full calendar) of the Gregorian calendar and a leap year starting on Tuesday of the 11-day slower Julian calendar. In the Swedish calendar it began as a leap year starting on Monday and remained so until Thursday, February 29. By adding a second leap day (Friday, February 30) Sweden reverted to the Julian calendar and the rest of the year (from Saturday, March 1) was in sync with the Julian calendar. Sweden finally made the switch from the Julian to the Gregorian calendar in 1753.