644

Millennium:	1st millennium
Centuries:	6th century – 7th century – 8th century
Decades:	610s 620s 630s – 640s – 650s 660s 670s
Years:	641 642 643 – 644 – 645 646 647

644 by topic
Politics
State leaders – Sovereign states
Birth and death categories
Births – Deaths
Establishment and disestablishment categories
Establishments – Disestablishments

644 in other calendars
Gregorian calendar	644 DCXLIV
Ab urbe condita	1397
Armenian calendar	93 ԹՎ ՂԳ
Assyrian calendar	5394
Bengali calendar	51
Berber calendar	1594
Buddhist calendar	1188
Burmese calendar	6
Byzantine calendar	6152–6153
Chinese calendar	癸卯年 (Water Rabbit) 3340 or 3280 — to — 甲辰年 (Wood Dragon) 3341 or 3281
Coptic calendar	360–361
Discordian calendar	1810
Ethiopian calendar	636–637
Hebrew calendar	4404–4405
Hindu calendars
- Vikram Samvat	700–701
- Shaka Samvat	566–567
- Kali Yuga	3745–3746
Holocene calendar	10644
Iranian calendar	22–23
Islamic calendar	23–24
Japanese calendar	N/A
Julian calendar	644 DCXLIV
Korean calendar	2977
Minguo calendar	1268 before ROC 民前1268年
Seleucid era	955/956 AG
Thai solar calendar	1186–1187

Wikimedia Commons has media related to 644.

King Oswine of Deira (644–651)

Year 644 (DCXLIV) was a leap year starting on Thursday (link will display the full calendar) of the Julian calendar. The denomination 644 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.

Events

Valentinus, Byzantine general, attempts to usurp the throne of his son-in-law Constans II. He appears at the gates of Constantinople with a contingent of Byzantine troops and demands to be crowned emperor. His claim is rejected and Valentinus is lynched by the populace.^[1]

Oswine, son of the late king Osric of Deira, manages despite armed objections from king Oswiu of Bernicia, to establish himself as king of Deira (Northern England). His succession, probably the choice of the people of Deira, splits the Kingdom of Northumbria.^[2]

November 6 – Caliph Umar, age 65, dies of wounds inflicted on November 3 by the Persian slave Piruz Nahavandi at Medina after a 10-year reign. On his death bed he appoints a committee to determine his successor. They select Uthman ibn Affan who becomes caliph of the Rashidun Caliphate.

Emperor Taizong of the Tang Dynasty sends a Chinese expeditionary force to invade and annex the Tarim Basin kingdom of Karasahr in Xinjiang, a vassal of the Western Turkic Khaganate. The oasis state is conquered and Western Turks to assist Karasahr are defeated by the Tang forces.^[3]