The real foundations of modern Delhi, however, were laid in 736 AD by the Tomar Rajput rulers who built the fortified Lal Kot near Mehrauli. In 1180, the Chauhans expanded this settlement and established Qila Rai Pithora, considered the first city of Delhi. Hardly any remnants of this original settlement can be found today, though some of its walls were used to build the Qutb Minar in the 13^th century AD.

The builder of Qutb Minar, Qutb-ud-din-Aibak, founded the slave dynasty or the Delhi Sultanate with its base at Lal Kot. In 1290, Ala-ud-din Khilji, the most dynamic of the Delhi sultans came to power in Delhi. He introduced widespread agrarian reforms, established a formal code of administration and extended his empire down to the Deccan plateau in the south. Khilji also established the second city of Siri in 1303, in the southern area now known as Hauz Khas.

With the ascendancy of the Tughlaq dynasty, the third city of Tughlaqabad was set up about 8 kms from Lal Kot. This citadel habitation was soon abandoned when the capital of the Tughlaqs was shifted down south to Daulatabad. Now, only crumbling ruins of the fort with some buildings and a mosque remain. Delhi regained its position of eminence once again, when the capital was shifted back in 1327 and the eccentric ruler Mohammad-bin-Tughlaq laid out the fourth city of Jahanpanah between Lal Kot and Siri. In 1354, his successor Feroz Shah Tughlaq established the fifth city Firozabad, next to Yamuna river. Not much of this city remains, except the dilapidated Firoz Shah Kotla palace area.

In 1398, the Mongolian army of Timur invaded Delhi and plundered it. The Lodi dynasty, which came to power in the 15^th century, constructed several fine monuments that are well preserved around the Lodi Garden area. The increasing power of the Lodis was cut short in 1526, when Ibrahim Lodi died fighting Babur on the plains of Panipat, close to Delhi. A descendant of Timur and Chenghiz Khan, Babur took control of the kingdom, but shifted his capital to Agra. His son Humayun again brought it back to Delhi in 1534, calling the new city Din Panah till Sher Shah Suri drove him out in 1540. Sher Shah, the great administrator who expanded his kingdom across the plains of India and built the arterial Grand Trunk Road, re-built the city and named it Shergarh. The ramparts of this city, now known as Purana Qila, lie to the southwest of New Delhi.

In 1555 Humayun returned to reclaim Delhi, but died in 1556. His wife, Haji Begum built the magnificent red sandstone tomb at Nizamuddin that served as the blueprint for later Mughal mausoleums, including the Taj Mahal. While Humayun’s son Akbar shifted the capital once again to Agra, his grandson Shah Jahan moved back to set up Shahjahanabad in 1628. This elaborately laid out seventh city with the Red Fort, grand buildings and bustling markets of Chandni Chowk became the centre of power until his successor Aurangzeb moved down south. Over several decades, the prowess of the Mughals declined and Delhi was invaded by the Persian king Nadir Shah in 1739. Crushing the inept ruler Mohammad Shah, Nadir Shah plundered the city and the Red Fort, carrying back the exquisite Peacock Throne among other booty.

As the Mughal dynasty faded into a puppet regime, various local chieftains like the Jats and Marathas invaded Delhi. Finally, in 1803 the British moved in and removed the last Mughal, Bahadur Shah from his seat in the Red Fort. Though the capital of the British Empire was in Calcutta, the rulers continued to occupy Delhi for its strategic importance. The Mutiny against British rule in 1857 that was triggered by rebellious Indian soldiers in the barracks of Meerut, soon spread to Delhi. Bahadur Shah was declared the Emperor of Hindustan, and under his titular leadership, the mutineers fought pitched battles against colonial rule. The Mutiny was suppressed however, and the British regained control over the Red Fort and Delhi. During the coronation of King George V in 1911, a durbar (audience) was held in Delhi where it was declared that the capital of India would be shifted here from Calcutta.

Work began soon, with the famous British architect Edwin Lutyens being commissioned to build the new city. New Delhi, crowned by the classical Rashtrapati Bhavan that housed the Viceroy, the parliament, offices of government and spacious bungalows, was laid out as the new capital. In 1931, it was officially inaugurated and remained the seat of British governance till independence in 1947.