1806 followed by 1807
1806 (MDCCCVI) was a common year starting on Wednesday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1806th year of the Common Era (CE) and Anno Domini (AD) designations, the 806th  year of the 2nd millennium, the 6th  year of the 19th century, and the  7th   year of the 1800s decade. As of the start of 1806, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.