What happened on December 24

Calendar year

Year 502 (DII) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Avienus and Probus. The denomination 502 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Head of the Catholic Church from 640 to 642

Pope John IV was the bishop of Rome from 24 December 640 to his death on 12 October 642. His election followed a four-month vacancy. He wrote to the clergy of Ireland and Scotland to tell them of the mistakes they were making with regard to the time of keeping Easter and condemned Monothelitism as heresy.

Imperial dynasty of China (618–907)

The Tang dynasty, or the Tang Empire, was an imperial dynasty of China that ruled from 618 to 907, with an interregnum between 690 and 705. It was preceded by the Sui dynasty and followed by the Five Dynasties and Ten Kingdoms period. Historians generally regard the Tang as a high point of Chinese civilisation, and a golden age of cosmopolitan culture.

Conflict between Qarmatians and Fatimids

The first Qarmatian invasion of Egypt took place in 971, when the Qarmatians of Bahrayn unsuccessfully invaded Egypt, which had recently been conquered by the Fatimid Caliphate. Both the Qarmatians and the Fatimids were offshoots of the Isma'ili sect of Shi'a Islam, but belonged to different and rival branches. Following the takeover of Egypt under the general Jawhar in 969, the Fatimids began their expansion into the Levant.

Religious wars of the High Middle Ages

The Crusades were a series of military campaigns launched by the papacy between 1095 and 1291 against Muslim rulers for the recovery and defence of the Holy Land, as part of a wider crusading movement. The First Crusade was proclaimed by Pope Urban II at the Council of Clermont in November 1095—a call to arms for Christians to reconquer Jerusalem from the Muslims, with promises of spiritual reward. By this time, the papacy's position as head of the Catholic Church had strengthened, and earlier conflicts with secular rulers and wars on the frontiers of Western Christendom had prepared it for the direction of armed force in religious causes.