621

621 in various calendars
Gregorian calendar	621; DCXXI
Ab urbe condita	1374
Armenian calendar	70; ԹՎ Հ
Assyrian calendar	5371
Balinese saka calendar	542–543
Bengali calendar	28
Berber calendar	1571
Buddhist calendar	1165
Burmese calendar	−17
Byzantine calendar	6129–6130
Chinese calendar	庚辰年 (Metal Dragon); 3318 or 3111; — to —; 辛巳年 (Metal Snake); 3319 or 3112
Coptic calendar	337–338
Discordian calendar	1787
Ethiopian calendar	613–614
Hebrew calendar	4381–4382
Hindu calendars
- Vikram Samvat	677–678
- Shaka Samvat	542–543
- Kali Yuga	3721–3722
Holocene calendar	10621
Iranian calendar	1 BP – 0 BP
Islamic calendar	1 BH – 0 BH
Japanese calendar	N/A
Javanese calendar	511–512
Julian calendar	621; DCXXI
Korean calendar	2954
Minguo calendar	1291 before ROC; 民前1291年
Nanakshahi calendar	−847
Seleucid era	932/933 AG
Thai solar calendar	1163–1164
Tibetan calendar	阳金龙年; (male Iron-Dragon); 747 or 366 or −406; — to —; 阴金蛇年; (female Iron-Snake); 748 or 367 or −405

Millennium:	1st millennium
Centuries:	6th century; 7th century ; 8th century;
Decades:	600s; 610s; 620s ; 630s; 640s;
Years:	618; 619; 620; 621 ; 622; 623; 624;

Year 621 (DCXXI) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. The denomination 621 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

Emperor Heraclius concludes a peace agreement (in exchange for an annual tribute) with the Avars on the Balkan Peninsula, giving him a free hand to assemble Byzantine forces in Asia Minor, for non-military expenditure against the Persian Empire.^[1]
The city of Málaga, in southern Spain in the province of Spania, is conquered by the Visigoths.^{[citation needed]}

King Sisebut dies after a 9-year reign and is succeeded by his son Reccared II (just a child).^[2] Reccared is placed on the throne by the Visigothic nobility, but dies after two months. Suintila, his half-uncle and regent, becomes king of the Visigothic Kingdom.

Emperor Gaozu delegates control of his military and civil administration in the east to his second son, Li Shimin. He concentrates on reforming coinage (→ Kaiyuan Tongbao) and taxation.
May 28 – Battle of Hulao: Li Shimin defeats the numerically superior army of Dou Jiande near the Hulao Pass.
June 4 – Wang Shichong, self-declared emperor, surrenders to Li Shimin at Luoyang following Dou Jiande's defeat. Gaozu spares his life, but he is later assassinated.

Islamic tradition says Muhammad visited heaven aboard the winged mount Buraq, in the Isra wal-Miraj, (the Night Journey), from Mecca to Jerusalem, then to heaven from Jerusalem's Temple Mount, then back to Mecca.

The Chinese establish an imperial bureau for the manufacture of porcelain. Their technology will advance further under the Tang dynasty (approximate date).