The second city of Delhi was built by Ala-ud-Din Khalji at Siri, three miles northeast of the Qutab Minar(near what is today Hauz Khaus and the Asian Games Village). The third city of Delhi was built by Ghiyas-ud-Din Tughluq (1320-25) at Tughlakabad but had to be abandoned in favor of the old site near because of a scarcity of water. The ruins of Tughlakabad are located on the present-day Delhi-Haryana border towards Faridabad.
His successor, Muhammad ibn Tughluq, extended the city farther northeast and built new forticications around it. It then became the fourth city of Delhi, under the name Jahanpanah. The new settlements were located between the old cities near the Qutab Minar and Siri Fort.
Muhammad ibn Tughluq's successor, Firuz Shah Tughluq, abandoned this site altogether and in 1354 moved his capital farther north near the ancient site of Indraprastha. Thus, the fifth city of Delhi, Firuzabad, was founded on what is now the Firoz Shah Kotla area. Delhi was invaded and partially destroyed by Timur at the end of the 14th century, and the last of the sultan kings moved the capital to Agra. Babur, the first Mughal ruler, reestablished Delhi as the seat of his empire in 1526. His son and successor, Humayun, built a new city on the site of the previously demolished Firuzabad and called in Din Panah.
Sher Shah, who overthrew Humayun in 1540, razed Din Panah and built his capital, the Sher Shahi (the Old Fort or Purana Qilah), as the sixth city of Delhi.
Delhi once again lost importance when the Mughal emperors Akbar (1556-1605) and Jahangir (1605-1627) moved their headquarters to Fatehpur Sikri (near Agra) and Agra, respectively. The city was restored to its glory in 1638 when the son of Jahangir, Shah Jahan, laid the foundations of the seventh city of Delhi, Shahjahanabad. What was Shahjahanabad has come to be known as Old Delhi. The greater part of the city is still confined within the space of Shah Jahan's walls and several gates built during his rule -- the Kashmiri Gate, the Delhi Gate, the Turkman Gate, and the Ajmeri Gate -- still stand.
With the fall of the Mughal empire during the mid-18th century, the city
of Delhi witnessed many invasions and power changes. The arrival of the
British in 1803 marked the beginning of a new period in Delhi's history.
Under British rule, Delhi grew to become a large city. In 1912 the
British moved the capital of British India from Calcutta in West Bengal to
the partially completed New Delhi. Construction of New Delhi was
completed by 1931.