Adoption of the Gregorian calendar the Empire (except Scotland, which had already done so from 1600) changed the start of the civil year from 5 April to 1 January. Consequently, the custom of dual dating (giving a date in both old and new styles) can refer to the Julian/Gregorian calendar change, or to the start of year change, or to both. The British tax year traditionally began on Lady Day (25 March) on the Julian calendar and thus became 5 April, which was the "Old Style" equivalent. A 12th skipped Julian leap day in 1800 changed its start to 6 April. It was not changed
Decimal calendar calendar. It consisted of twelve months, each divided into three "décades" of ten days, with five or six intercalary days called "sansculottides". The calendar was abolished by Napoleon on January 1, 1806. The modern Gregorian calendar does not use decimal units of time, however several proposed calendar systems do. None of these have achieved widespread use. Decimal calendar A decimal calendar is a calendar which includes units of time based on the decimal system. The original Roman calendar consisted of ten months (however, the calendar year only lasted 304 days, with 61 days during winter not assigned to any month).