|Centuries:||5th century – 6th century – 7th century|
|Decades:||560s 570s 580s – 590s – 600s 610s 620s|
|Years:||588 589 590 – 591 – 592 593 594|
|591 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1344|
|Bahá'í calendar||−1253 – −1252|
|English Regnal year||N/A|
|Chinese calendar||庚戌年 (Metal Dog)
3287 or 3227
— to —
辛亥年 (Metal Pig)
3288 or 3228
|- Vikram Samvat||647–648|
|- Shaka Samvat||513–514|
|- Kali Yuga||3692–3693|
|Igbo calendar||−409 – −408|
|Iranian calendar||31 BP – 30 BP|
|Islamic calendar||32 BH – 31 BH|
|Minguo calendar||1321 before ROC
|Thai solar calendar||1134|
|Wikimedia Commons has media related to 591.|
Year 591 (DXCI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. The denomination 591 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.
- Byzantine–Sassanid War: Emperor Maurice, seeing an opportunity to end the prolonged war to the advantage of Constantinople, assists Khosrau II to regain the Persian throne. He sends an Byzantine army (35,000 men) under Narses into Mesopotamia through Syria. At the same time an expeditionary force in Armenia advance through Caucasian Iberia into Media (modern Azerbaijan).
- Battle of Blarathon: A Persian army of about 40,000 men under king Bahrām VI is defeated, in the lowlands near Ganzak (northwestern Iran), by the Byzantines. Bahrām flees to seek refuge with the Turks in Central Asia and settled in Fergana. However, after some time, he is murdered by a hired assassin of Khosrau II.
- Summer – Maurice begins a series of military expeditions to defend the Balkan provinces from the Avars and Slavs. He stabilishes the Danube frontier (Limes Moesiae) from the Delta to the fortress city of Singidunum (Belgrade) and permit the Byzantines to reassert their authority in the interior.
- Agilulf, cousin of Authari (called "the Thuringian"), is raised on the shield — a ceremonial investment — by Lombard warriors in Milan. He becomes king of the Lombard Kingdom, on advice of the Lombard dukes (dux). Agilulf marries widowed queen Theodelinda and is baptized to please her.
- Arechis I succeeds his uncle Zotto as the second Duke of Benevento.
- A locust swarm destroys the harvest in Italy (approximate date).
- Khosrau II is reinstalled as king of the Persian Empire. Peace with Constantinople is concluded after almost a war of 20-years. Maurice receives the Persian provinces of Armenia and Georgia. The recognition of the traditional frontiers and the cessation of subsidies for the Caucasus forts; leaves the Byzantines in a dominant position in their relations with Persia.
- Pope Gregory I criticized the bishops of Arles and Marseille for allowing the forced baptism of Jews in Provence (France).
- Jnanagupta, Afghan Buddhist monk, translates the Vimalakirti Sutra into Chinese.
- Cadwallon ap Cadfan, king of Gwynedd (approximate date)
- Gundeberga, queen of the Lombards
- Li Xiaogong, prince of the Tang Dynasty (d. 640)
- Su Dingfang, general of the Tang Dynasty (d. 667)
- Aredius, abbot and saint
- Faroald I, duke of Spoleto (or 592)
- Garibald I, duke of Bavaria (b. 540)
- John Mystacon, Byzantine general (approximate date)
- Peter III of Raqqa, Patriarch of Antioch
- Li Delin, Chinese official and writer (b. 531)
- Yan Zhitui, Chinese scholar and official (b. 531)
- Zotto, founder of the Duchy of Benevento
- Gumilev L.N.Bahram Chubin, p. 229–230
- Usanova M. Ismoil Somonii waqfnomasi, p. 29
- Rome at War (p. 60). Michael Whitby, 2002. ISBN 1-84176-359-4