1856 followed by 1857
1856 (MDCCCLVI) was a leap year starting on Tuesday of the Gregorian calendar and a leap year starting on Sunday of the Julian calendar, the 1856th year of the Common Era (CE) and Anno Domini (AD) designations, the 856th  year of the 2nd millennium, the 56th  year of the 19th century, and the  7th   year of the 1850s decade. As of the start of 1856, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.