The Tanguts invade China from the northwest in 1040, apparently with the intention of conquering all of Song China, but the Chinese, with difficulty, repulse them.

The Song emperor agrees to a deal similar to the one struck with the Khitans at the beginning of the century: an annual tribute of silver, silk, and tea.

Chaghri and Tughril have fought against the Ghaznavids between 1038 and 1040, usually with hit and run maneuvers.

When the Seljuq leaders begin raising an army, they are seen as a threat to the Ghaznavid territories.

Following the looting of border cities by Seljuq raids, Sultan Mas'ud I decides to expel the Seljuqs from his territories.

Tughril had suggested to continue with the hit and run operations, but Chagri, who commands the Seljuq army, prefers to fight.

During the march of Sultan Mas'ud's army to Sarakhs, the Seljuq raiders harass the Ghaznavid army with hit-and-run tactics.

Seljuq raiders also destroye the supply lines of the Ghaznavids, cutting them off from the nearby water wells.

The discipline and morale of the Ghaznavid army drops precipitously.

Finally, on May 23, 1040, around twenty thousand Seljuq soldiers engage in battle with an estimated fifty thousand Ghaznavid soldiers in Dandanaqan, between Merv and Sarakhs; the Seljuqs are victorious.

They soon occupy Khorasan and the cities of the area, encountering little resistance.

A kurultai is held after the battle, by which the nascent empire is divided between the two brothers.

While Tughril reigns in the west (comprising modern western Iran, Azerbaijan and Iraq), Chaghri reigns in eastern Iran, Turkmenistan, and Afghanistan.

Hungarian forces had invaded Bohemia in 1040 to assist Duke Bretislav I against Holy Roman Emperor Henry III.

Hungarian chronicles recount that Peter preferred the company of Germans and Italians, which had made him unpopular among his subjects.

He has introduced new taxes, seized Church revenue and deposed two bishops.

John recalls Maniakes and has him imprisoned on charges of treason in 1040 after the disastrous desertions of the Normans, Salernitans, and Varangians from Maniakes' army.

Local people in the Theme of Bulgaria rebel against the Empire in during the summer of 1040.

The uprising spreads and the rebels very quickly take over control over northern part of Pomoravlje and liberate Belgrade.

The origins of Peter Delyan are not clear.

He claims that he is a son of emperor Gavril Radomir and grandson of Samuel of Bulgaria, but he could also have been local who became the leader of an uprising against Constantinople’s rule over Bulgaria and claimed to be Samuel's grandson to justify his proclamation as Tsar Peter II of Bulgaria in Belgrade in 1040.

He is soon joined as co-ruler by Prince Alusian, a member of the ruling family, and leads Bulgarian forces in an open rebellion against Constantinople’s rule in a bid for independence.

Anushtakin Al-Dizbari has attempted to deprive Mu'izz al-Dawla Thimal of his remaining possessions.

Thimal had lost several towns, although he had managed to retain Rahba.

He had then married his brother Salih's widow.

The imperial forces attack sometime around 1040 and force Thimal and his cousin Mukallad to pay tribute.

Lahore appears as the capital of the Punjab for the first time under Anandapala—the Hindu Shahi king who is referred to as the ruler of (hakim i lahur)—after leaving the earlier capital of Waihind.

Few references to Lahore remain from before its capture by Sultan Mahmud of Ghaznavi in the eleventh century.

The sultan had taken Lahore after a long siege and battle in which the city had been torched and depopulated.

In 1021, Sultan Mahmud had appointed Malik Ayaz to the throne and made Lahore the capital of the Ghaznavid Empire.

As the first Muslim governor of Lahore, Ayaz has rebuilt and repopulated the city.

He has added many important features, such as city gates and a masonry fort, built in 1037–1040 on the ruins of the previous one, which had been demolished in the fighting.

The present Lahore Fort stands on the same location.

Under Ayaz's rule, the city has become a cultural and academic center, renowned for poetry.

The tomb of Malik Ayaz can still be seen in the city’s Rang Mahal commercial area.

Bulgarian tsar Peter II Delyan takes Niš and …

…Skopje from the Empire, first co-opting and then eliminating another potential leader in the person of one Tihomir, who had led a rebellion in the region of Dyrrachium.

After this, …

…Petar II marches on Thessalonica, where the Emperor Michael IV is staying.

Defeated, he flees, leaving his treasury to a certain Michael Ivač.

The latter, who is probably a son of Ivač, a general under Samuel of Bulgaria, promptly turns over the bulk of the treasury to Petar outside the city.

Thessalonica remains in imperial hands, but …