Five dynasties
The Sultanate began in 1206 when Qutb ud-Din Aibak, a Turkic military slave (mamluk) commanding the Indian conquests of the Ghurid empire, became independent ruler at his master’s death — the first of the “Slave” or Mamluk dynasty, whose victory tower, the Qutb Minar, still stands over Delhi. Four dynasties followed: the Khaljis (whose Alauddin conquered deep into the Deccan and ran famous price-control economics to pay his army), the Tughluqs, the diminished Sayyids, and the Afghan Lodis.
The Mongol shield
The Sultanate’s underrated world-historical role: through the 13th and early 14th centuries it repeatedly repelled Mongol invasions — one of very few major states anywhere in Eurasia to do so consistently — absorbing attacks that reached Delhi’s suburbs. Northern India’s cities and institutions were spared the fate of Baghdad largely behind the Sultanate’s cavalry.
Zenith and misadventure
Under the Tughluqs the Sultanate briefly held most of the subcontinent — and produced its most notorious ruler, Muhammad bin Tughluq (r. 1325-1351), whose brilliant, catastrophic experiments (the forced capital transfer to Daulatabad; the forgery-drowned token currency) unravelled the over-extended state. The Deccan and Bengal broke away mid-century; the Vijayanagara empire rose in the south explicitly to contain sultanate power.
In 1398 Timur (Tamerlane) invaded, shattered the Delhi army, and gave the capital a sack from which contemporaries said it took a century to recover — his chroniclers count the captives in the tens of thousands and Delhi’s dead beyond counting. The Sultanate that continued was a regional power among rivals.
End at Panipat
In 1526 the last sultan, Ibrahim Lodi, met Babur’s smaller army — with its field artillery and flanking horse-archer tactics — at Panipat, and died on the field. The victor’s dynasty, the Mughals, inherited the Sultanate’s capital, bureaucratic vocabulary, and Indo-Islamic architectural and culinary synthesis: three centuries of sultans had made Delhi the political centre of gravity of India, which — through Mughals, Company, and Raj to the present republic — it has essentially remained.