January 11 – Nika riots in Constantinople: Anger among the supporters of different chariot teams--the Blues and the Greens--escalates into violence towards the emperor. For the next five days the capital is in chaos. The fires that start during the tumult result in the destruction of much of the city, including the Hagia Sophia. The insurrection is put down a week later by Belisarius and Mundus; 30,000 people are killed in the Hippodrome.
September – Justinian I signs a peace treaty, the "Eternal Peace", with the Persian king Khosrau I, ending the Iberian War. Both sides agree to return all occupied territories, and Justinian makes a one-off payment of 110 centenaria (11,000 pounds of gold), as a contribution to the defense of the Caucasus passes.
June 21 – A Byzantine expeditionary fleet under Belisarius sails in 500 transports, escorted by 92 war vessels (dromons), manned by 20,000 seamen from Constantinople, to attack the Vandals in Africa, via Greece and Sicily. The fleet carries 10,000 infantry, about half Byzantine and half foederati, and 5,000 cavalry, consisting of 3,000 Byzantine horsemen, 1,000 foreign allies (Huns and Heruli) and 1,500 of Belisarius' retainers (bucellarii). On the flagship Belisarius is accompanied by his military secretary Procopius and his wife Antonina.
September – Belisarius arrives at Sicily, which he uses as a staging area, with the permission of the Ostrogoth queen Amalasuntha, daughter of Theodoric the Great and regent of Italy. The Ostrogoths help him with supplies and the fleet is prepared for the final attack.
September 9 – The Byzantine army lands at Caput Vada (modern Tunisia). Belisarius marches his army northwards, towards Carthage (over 140 miles), following the coast, accompanied by the fleet and shadowed by Gelimer. During the march, the Vandal towns fall without a fight.
September 13 – Battle of Ad Decimum: Gelimer attempts to ambush the Byzantines in a defile at the "10th milestone" from Carthage; due to inadequate coordination and the alertness of Belisarius, the attack is repulsed and the Vandals are scattered into the desert. Belisarius enters the capital and orders his soldiers not to kill or enslave the population. The fleet is stationed in the Lake of Tunis.
December 15 – Battle of Tricamarum: Gelimer assembles an army of about 50,000 men at Bulla Regia (Numidia), and advances towards Carthage. Belisarius moves out to meet the Vandals; he leads the Byzantine cavalry (5,000 men) into battle. Without waiting for his infantry to come up, he charges, despite odds of almost 10-to-1, and throws Gelimer in confusion. Belisarius captures the Vandal camp by storm. Tzazo is killed in an all-cavalry fight, and Gelimer is forced to seek refuge in the mountains of Tunis with the Berbers.
April – Belisarius leaves a small force in Africa under the Byzantine general Solomon, to continue the subjugation of the province. He is appointed governor (Exarch) and pacifies with success the Moorish tribes. Malta becomes a Byzantine province (until 870).
Summer – Belisarius arrives in Constantinople and is permitted by Emperor Justinian I to celebrate a triumph, the first non-imperial triumph for over 500 years. In the procession are paraded the spoils of the Temple of Jerusalem and the Vandal treasure.
Justinian I commemorates the victory against the Vandals by stamping medals in his honor with the inscription "Gloria Romanorum" (approximate date).
October 2 – King Athalaric dies of tuberculosis, age 18, having dissipated his youth in drink and debauchery. His mother, Amalasuntha, proposes to her cousin Theodahad, the kingdom's largest landowner and her father's last male heir, that he share the throne with her but that he will be king of the Ostrogoths in name only. Theodahad has secret conversations with the Byzantine ambassador, and promises to turn over Tuscany in exchange for a large sum of money, the rank of senator, and permission to live at Constantinople.
December 9 - Belisarius enters Rome through the Asinarian Gate; the Gothic garrison (4,000 men) flee the capital. He sends an urgent request for reinforcements to Justinian I, meanwhile preparing Rome for a siege by bringing in great quantities of food and other supplies.
Winter - Belisarius sets up his headquarters on the Pincian Hill and repairs the neglected city walls of Rome. He stations a 5,000-man garrison, of whom half are his personal bodyguard (bucellarii). To hold parts of the city, he recruits 20,000 young Romans to man the walls.
March – Belisarius sails to Carthage with 1,000 men, to suppress a mutiny against Solomon. Meanwhile the capital is besieged by 9,000 rebels, including many Vandals, under Stotzas. Belisarius defeats the mutineers and hurries back to Sicily.
Vitiges sets up seven camps, overlooking the main gates and access routes to the city, in order to starve it out. He blocks the Roman aqueducts that are supplying Rome with water, necessary both for drinking and for operating the corn mills.
April – The Goths capture the Portus Claudii at Ostia; the harbor is left unguarded by the Romans. Belisarius is forced to unload his supplies at Antium (modern Anzio); he sends urgent messages for reinforcements to Constantinople.
April 9 – Belisarius receives his promised reinforcements: 1,600 cavalry, mostly of Hunnic or Slavic origin and expert bowmen. He starts, despite shortages, raids against the Gothic camps and Vitiges is forced into a stalemate.
June – In Rome, famine brings the city to despair; Belisarius sends his secretary Procopius to Naples for more reinforcements and supplies. Vitiges arranges a three-month armistice for Gothic envoys to travel to Constantinople.
November – Belisarius brings his long-awaited reinforcements, namely 3,000 Isaurians and 1,800 cavalry embarked in Ostia, along with a supply convoy, safely to Rome. The Goths are forced to abandon the Portus Claudii.
December – Belisarius sends John "the Sanguinary" with a force of 2,000 men towards Picenum, to plunder the east coast of Italy. He arrives at Ariminum (Rimini), where he is welcomed by the local Roman population.
Eastern Wei sends an advance guard of three army columns through the Tong Pass, to attack Western Wei. The Western army under Yu-Wen Tai defeats one of the columns while the others retreat. Yu-Wen follows up, but runs into the main Eastern army (200,000 men). The Westerners are pushed back through the pass, and the Eastern army emerges from the mountains. Unexpectedly they are charged in the flank by 10,000 Western cavalry, and 6,000 Easterners are killed and 70,000 captured.
The first time since Emperor Justinian's decree of 533 that John became the Bishop of Rome, Chief Bishop of all the churches. The supremacy of the Bishop of Rome over the Church could actually be implemented by Vigilius.
^Isidore of Seville, History of the Goths, chapter 40. Translation by Guido Donini and Gorden B. Ford, Isidore of Seville's History of the Goths, Vandals, and Suevi, second revised edition (Leiden: E.J. Brill, 1970), p. 19.