He was in charge of the Ghurid territories in northern India, and after Muhammad Ghori's assassination in 1206, he established his own independent rule in Lahore, and laid the foundations for the Sultanate of Delhi.

During the Khwarazmian-Ghurid wars, he was captured by the scouts of Sultan Shah; after the Ghurid victory, he was released and highly favoured by Muhammad Ghori.

Aibak expanded the Ghurid power in northern India by conquering and raiding several places in the Chahamana, Gahadavala, Chaulukya, Chandela, and other kingdoms.

After the assassination of Muhammad Ghori in March 1206, Aibak fought with another former slave-general Taj al-Din Yildiz for control of Ghurid territories in north-western India.

He nominally acknowledged the suzerainty of Muhammad Ghori's successor Ghiyasuddin Mahmud, who officially recognized him as the ruler of India.

Aibak was succeeded by Aram Shah, and then by his former slave and son-in-law Iltutmish, who transformed the loosely-held Ghurid territories of India into the powerful Delhi Sultanate.

[5] During the Ghurid conflicts with the Khwarazmian ruler Sultan Shah, Aibak was responsible for the general maintenance of the horses, as well as their fodder and equipment.

[7] Aibak was one of the generals of the Ghurid army that were defeated by the forces of the Chahamana ruler Prithviraja III at the First Battle of Tarain in India.

[10] After his victory at Tarain, Muhammad Ghori assigned the former Chahamana territory to Aibak, who was placed at Kuhram (present-day Ghuram in Punjab, India).

[11][4] The exact nature of this assignment is not clear: Minhaj describes it as an iqta', Fakhr-i Mudabbir calls it a "command" (sipahsalari), and Hasan Nizami states that Aibak was made the governor (ayalat) of Kuhram and Samana.

Majumdar adds that Firishta may have confused the Chaulukya ruler Bhima with Bhima-simha, who - according to the Kharatara Gaccha Pattavali - was the governor of Hansi in 1171 CE.

Historian K. A. Nizami finds Isami's account unreliable and theorizes that the Sultan may have sought Aibak's help in planning further Ghurid expansion in India.

[12] In 1194, Muhammad Ghori returned to India and crossed the Jamuna with an army of 50,000 horses and at the Battle of Chandawar defeated the forces of the Gahadavala king Jayachandra, who was killed in action.

[26][27] Although the Ghurids did not gain complete control over the Gahadavala kingdom, the victory provided an opportunity for them to establish military stations at many places in the region.

[29] Aibak's army then marched to the Chaulukya capital Anhilwara: the defending king Bhima II fled the city, which was plundered by the invaders.

The Chandela chief minister Ajayadeva resumed hostilities but was forced to seek negotiations when the Ghurids cut off the water supply to the fort.

[33] Meanwhile, the Ghurid commander Bakhtiyar Khalji subjugated the petty Gahadavala chiefs in eastern Uttar Pradesh and the Bihar region.

Bakhtiyar was killed by his subordinate Ali Mardan Khalji at Devkot in 1206, around the same time Sultan Muhammad Ghori was assassinated.

Nevertheless, he instructed his subordinate Qaimaz Rumi – the governor of Awadh – to march to Lakhnauti in Bengal, and assign suitable iqta's to the Khalji amirs.

[43] Tajul-Ma'asir, a contemporary chronicle by Hasan Nizami, suggests that Muhammad Ghori appointed Aibak as his representative in India after his victory at Tarain.

[44] Fakhr-i Mudabbir, another contemporary chronicler, states that Muhammad Ghori formally appointed Aibak as the viceroy of his Indian territories only in 1206 when he was returning to Ghazni after suppressing the Khokhar rebellion.

According to this chronicler, Aibak was promoted to the rank of malik and appointed heir apparent (wali al-ahd) of the Sultan's Indian territories.

The Sultan's unexpected death left three of his main slave-generals – Aibak, Taj al-Din Yildiz, and Nasir ad-Din Qabacha – in positions of power.

[47][4] Meanwhile, in and around Ghazni, the Sultan's slaves fought with his nobles for control of the Ghurid Empire and helped his nephew Ghiyasuddin Mahmud ascend the throne.

After Sultan Mahmud confirmed him as the ruler of Ghazni and manumitted him, Yildiz marched to Punjab, intending to take control of the region.

[42] Aibak then sent his representative Nizamuddin Muhammad to Mahmud's headquarters at Firuz Kuh, seeking to expedite his request for the investiture.

In 1210, he fell down from a horse while playing chaugan (a form of polo on horseback) in Lahore, and died instantly when the pommel of the saddle pierced his ribs.

[50] Fakhr-i Mudabbir states that Aibak's soldiers – who included "Turks, Ghurids, Khurasanis, Khaljis, and Hindustanis" – did not dare to forcibly take even a blade of grass or a morsel of food from the peasants.

The 16th century Mughal chronicler Abu'l-Fazl criticizes Mahmud of Ghazna for "shedding innocent blood", but praises Aibak stating that "he achieved things, good and great".

[54] However, this may have been an erroneous addition made by a careless scribe, as Alauddin Ata Malik-i-Juwayni's Tarikh-i-Jahan-Gusha chronicle explicitly mentions that Aibak had no son.