May 4 – Battle of Montemaggiore: Lombard-Norman rebel forces, led by William, are again victorious, and defeat a Byzantine army (18,000 men) on the hill of Montemaggiore, near the River Ofanto.
At about this time, the number of enlisted soldiers in the Song dynasty Chinese military reaches well over 1,250,000 troops, an increase since 1022, when there were a million soldiers.
April 19 – Emperor Michael V Kalaphates banishes his adoptive mother and co-ruler Zoë, for plotting to poison him, to the island of Principo. His announcement as sole emperor leads to a popular revolt.
April 20 – Zoë is proclaimed as empress at an assembly in Hagia Sophia, along with her sister Theodora, as co-ruler. Michael V flees to the monastery of Stoudios, but is arrested, blinded and castrated.
June 11 – Zoë marries her third husband, a Byzantine bureaucrat who ascends as co-emperor Constantine IX at Constantinople. Theodora agrees to surrender her co-emperorship.
Summer – George Maniakes goes on a march through Apulia, plundering the towns that have declared for the Lombard rebels. Constantine IX recalls Maniakes to Constantinople.
George Maniakes revolts against Constantine IX and is declared emperor by his troops. He captures Pardos who has landed with an army at Otranto to take over his command.
Byzantine–Arab War: The Byzantines reconquer the fortress city of Edessa (modern Turkey), returning it to Christian hands, after 400 years of Islamic rule (approximate date).
Duklja secures its independence from the Byzantine Empire.
June 8 – Magnus the Good becomes king of Denmark after the death of Harthacnut. Despite a claim to the throne by Sweyn II, Magnus takes control of Denmark.
Spring – Emperor Constantine IX Monomachos sends a Byzantine expeditionary force to the Balkans against the rebellious George Maniakes, governor of the Catepanate of Italy. The two armies meet near Thessaloniki in northern Greece. The rebel army – better organized, seasoned and with superior leadership – is initially successful, but Maniakes is killed by an arrow at the moment of his triumph. After this, his army is routed.
Spring – A grand assembly at Melfi, with all the Norman and Lombard nobles acclaim Guaimar IV, duke of Apulia and Calabria. The territories are divided into 12 fiefdoms and distributed among Norman chieftains. William Iron Arm is granted Ascoli as a private fiefdom and his brother Drogo of Hauteville is granted Venosa. Count Rainulf II of Aversa, not present at the assembly, receives Siponto and recognizes Guaimar's suzerainty.
The Chinese military treatise of the Wujing Zongyao is written and compiled by scholars Zeng Gongliang (曾公亮), Ding Du (丁度), and Yang Weide (楊惟德), during the Song dynasty. It is the first book in history to include formulas for gunpowder, and its use for various bombs (thrown by sling or trebuchet catapult). It also describes the double-piston pump flamethrower and a thermoremanence compass, a few decades before Shen Kuo wrote of the first known magneticmariner's compass. Although emphasizing the importance of many weapons, it reserves high respect for the crossbow, and the ability of crossbowmen to fell charging units of nomadiccavalrymen.
May 5 – Pope Gregory VI becomes the 148th pope, following the resignation of Pope Benedict IX in exchange for money. There are growing allegations that simony is taking place during Gregory VI's reign.[12]
The Qingli Reforms, put forth by the Chinese statesman Fan Zhongyan in 1043,[14] are halted by their conservative ministerial peers, but will later influence reform efforts under Wang Anshi.[15]
Bao Zheng (Lord Bao), a Chinese government officer during the reign of Emperor Renzong of Song, writes a memorial to the throne. He warns about governmental corruption – and a foreseeable bankruptcy of the Chinese iron industry – if increasingly poorer families continued to be listed on the register for iron-smelting households (while rich households avoid being listed for fear of financial calamity). Apparently the government heeds the warning, and produces more iron products by the year 1078 than China ever had before.
September 25–28 – Rebel general Leo Tornikios (a nephew of Emperor Constantine IX) proclaims himself emperor at Adrianople, and besieges Constantinople. Byzantine troops personally led by Constantine repel him, and re-occupy the walls. Tornikios is forced to withdraw, while his followers start to abandon him. Finally, he is captured at a church in Boulgarophygon (modern Turkey), and is publicly blinded.[18][19][20]
Winter – Constantine IX allows the Pecheneg tribes to cross the Danube and settle permanently in Byzantine territory. He buys their alliance with presents, using them to attack his enemies (Bulgars and Magyars) in the rear, and so to prevent any southward advance of the Kievan Rus'.[21][22][23]
September 18 – Battle of Kapetron: A combined Byzantine-Georgian army, under Byzantine generals Aaronios and Katakalon Kekaumenos (supported by the Georgian duke Liparit IV), confronts the invading Seljuk Turks, led by Ibrahim Inal (a half-brother of Sultan Tughril), at Kapetron (near modern-day Pasinler). The Byzantines defeat their opposing Turkish forces in the flanks, but in the centre Ibrahim Inal captures Liparit, and can safely withdraw from Byzantine territory, laden with spoils and captives, including Liparit.[38]
Winter – Emperor Constantine IX sends an embassy with gifts and a ransom, to release Liparit IV to Tughril. However, the sultan sets Liparit free, on the condition that he will never again fight the Seljuks.
December – Bruno von Egisheim-Dagsburg, bishop of Toul, is selected as the new pope by an assembly at Worms - after canonical election in Rome next February, he assumes the name Pope Leo IX.
Spring – Pecheneg Revolt: Emperor Constantine IX decides to transfer 15,000 Pecheneg warriors from their positions in the Balkans to the eastern front. Upon approaching the Bosporus, the Pechenegs decide to turn back, and march through Bulgaria, until they reach the Byzantine city of Serdia. Later, joined by followers, the Pecheneg tribes raise the banner of revolt in Thrace.
^of Montecassino, Amatus (2004). Loud, Graham A. (ed.). The History of the Normans. Translated by Dunbar, Prescott N. Woodbridge, England and Rochester, NY: Boydell Press. pp. 86–87. ISBN9781843830788.
^David C. Douglas (1999). William the Conqueror, p. 1026. (Yale University Press).
^A.S (2014). "Benedict IX (1032 - 1044, 1045, 1047 - 1048)". A Corrupt Tree: An Encyclopaedia of Crimes committed by the Church of Rome against Humanity and the Human Spirit. Vol. I: The Unholy Popes and the Debasement of Western Civilization. Bloomington, IN: Xlibris Corporation. p. 169. ISBN9781483665375.