1756 followed by 1757
1756 (MDCCLVI) was a leap year starting on Thursday of the Gregorian calendar and a leap year starting on Monday of the Julian calendar, the 1756th year of the Common Era (CE) and Anno Domini (AD) designations, the 756th  year of the 2nd millennium, the 56th  year of the 18th century, and the  7th   year of the 1750s decade. As of the start of 1756, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.