1826 followed by 1827
1826 (MDCCCXXVI) was a common year starting on Sunday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1826th year of the Common Era (CE) and Anno Domini (AD) designations, the 826th  year of the 2nd millennium, the 26th  year of the 19th century, and the  7th   year of the 1820s decade. As of the start of 1826, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.