540s

Below are some of the important events that happened from 540 to 549.
540
Emperor Kimmei, reign of 29th emperor of Japan starts (540-571)
Vitiges of the Ostrogoths surrendered to the Byzantine army.
Ildibad succeeds Vitiges as king of the Ostrogoths.
Births
Authari, king of the Lombards
Pope Gregory I (approximate date)
Myrddin Wyllt, Welsh legend (approximate date)
Deaths
Dignaga, Buddhist founder of Indian logic
Dionysius Exiguus (approximate date)
Fridolin of Sackingen Irish missionary
Vedast, Frankish bishop
Vitiges, king of the Ostrogoths
Yifu, empress of Western Wei
Yujiulu, empress of Western Wei
541
Plague of Justinian: Bubonic plague appears suddenly in the Egyptian port of Pelusium. It spreads to Alexandria and, the following year, to Constantinople. This is the beginning of a 200-year long pandemic that will devastate Europe, the Middle East, and North Africa.
Totila is elected king by the Ostrogothic nobles after the death of his uncle Ildibad.
The Uyghurs come under the rule of the Hephthalites
Births
July 21 - Wendi, emperor of the Sui Dynasty
Deaths
Adhurgunbadh, Persian general
Eraric, king of the Ostrogoths
Ildibad, king of the Ostrogoths
542
Plague of Justinian: Bubonic plague kills at least 230,000 in Constantinople.
King Childebert I and his brother Chlothar I invade Visigothic Spain.
Births
Xiao Min Di, emperor of Northern Zhou
Xiao Ming Di, emperor of the Liang Dynasty
Deaths
August 27 - Caesarius, bishop of Arles
543
The Byzantine garrison (1,000 men) in Naples surrenders to the Ostrogoths.
King Khosrau I invades Syria.
The Hephthalites threaten the Persian Empire from the East. They extend their gain more territory in Central Asia.
King Pulakesi I starts the Chalukya Dynasty.
Births
Brunhilda, queen of Austrasia (approximate date)
Jing Di, emperor of the Liang Dynasty
Wu Di, emperor of Northern Zhou
Deaths
Octa, king of Kent (approximate date)
544
Belisarius defeats the Gothic army under king Totila.
King Khosrau I unsuccessfully attacks the Byzantine city of Dara.
Ly Bi is made emperor and starts the empire Van Xuan (modern Vietnam).
Births
Dugu Qieluo, empress of the Sui Dynasty
Jing Di, emperor of the Liang Dynasty
Yuwen Xian, prince of Northern Zhou
Deaths
Solomon, Byzantine general
October 18 - Saint Wenna
545
King Khosrau I signs a five-year truce with the Byzantine Empire.
Births
Abd Allah ibn Abd al Muttalib, father of Muhammad
Fei Di, emperor of Northern Qi
Deaths
Budic II, king of Brittany (approximate date)
Clotilde, Burgundian princess
Medardus, bishop of Vermandois (approximate date)
Stotzas, Byzantine rebel leader
546
The Ostrogoths under king Totila retake Rome.
Audoin succeeds Walthari as king of the Lombards.
Audoin leads the Lombards across the Danube and becomes an ally of the Byzantines.
Deaths
Walthari, king of the Lombards
547
Belisarius recaptures Rome from the Ostrogoths.
Theodebald becomes king of Austrasia.
King Ida starts the kingdom of Bernicia. He builds Bamburgh Castle.
The Tonkin revolt is stopped by the Chinese Liang Dynasty.
Births
Pei Ju
Empress Zhu Manyue
Deaths
Theodebert I, king of Austrasia (or 548)
Tribonian, Byzantine lawyer and writer of the Codex Justinianus.
Maelgwn Gwynedd, king of Gwynedd (approximate date)
Gao Huan
548
Emperor Justinian I removes Belisarius from military service.
Theudigisel names himself ruler over the Visigothic Kingdom.
Births
Xiao Zhuang, crown prince of the Southern Dynasties (approximate date)
Deaths
April 13 - Ly Nam De, emperor of Vietnam
Theodebert I, king of Austrasia (or 547)
June 28 - Theodora I, Byzantine Empress
Theudis, king of the Visigoths
549
Jianwen Di becomes ruler of the Liang Dynasty in China.
Agila becomes king of the Visigoths.
The Roman Catholic Diocese of Ossory is founded in Ireland.
The Ostrogoths under Totila recapture Rome.
Totila conquers the city of Perugia.