History of India
Akbar's son, Jahangir more or less followed father's policy. The Mughal dynasty ruled most of the Indian subcontinent by 1600. The reign of Shah Jahan was the golden age of Mughal architecture. He erected several large monuments, the most famous of which is the Taj Mahal at Agra, as well as the Moti Masjid, Agra, the Red Fort, the Jama Masjid, Delhi, and the Lahore Fort. The Mughal Empire reached the zenith of its territorial expanse during the reign of Aurangzeb and also started its terminal decline in his reign due to Maratha military resurgence under Shivaji. Historian Sir. J.N. Sarkar wrote, "All seemed to have been gained by Aurangzeb now, but in reality all was lost." The same was echoed by Vincent Smith: "The Deccan proved to be the graveyard not only of Aurangzeb's body but also of his empire".

Q: During whose reign did the Mughal Empire reach its greatest expanse?
Aurangzeb