Chinese calendar by mountain peoples. After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar () was introduced. It followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar; the year began with month 10 and ended with month 9, analogous to a Gregorian calendar beginning in October and ending in September. The intercalary month, known as the second "Jiǔyuè" (), was placed at the end of the year. The Qin calendar was used into the Han dynasty. Emperor Wu of Han introduced reforms halfway through his
Adoption of the Gregorian calendar the date of Easter astronomically using the instant of the vernal equinox and the full moon according to Kepler's "Rudolphine Tables" of 1627; this combination was referred to by the Protestant estates as the "improved calendar" ("Verbesserte Kalender") and considered to be distinct from the Gregorian. They finally adopted the Gregorian calculation of Easter in 1774. The remaining provinces of the Dutch Republic adopted the Gregorian calendar on 12 July 1700 (Gelderland), 12 December 1700 (Overijssel and Utrecht), 12 January 1701 (Friesland and Groningen) and 12 May 1701 (Drenthe). Sweden's transition to the Gregorian calendar was difficult and protracted. Sweden