sent a letter entitled Zafarnamah, which accused Aurangzeb of cruelty and betraying Islam. The letter caused him much distress and remorse. Guru Gobind Singh's formation of Khalsa in 1699 led to the establishment of the Sikh Confederacy and later Sikh Empire. Pashtun opposition The Pashtun revolt in 1672 under the leadership of the warrior poet Khushal Khan Khattak of Kabul, was triggered when soldiers under the orders of the Mughal Governor Amir Khan allegedly molested women of the Pashtun tribes in modern-day Kunar Province of Afghanistan. The Safi tribes retaliated against the soldiers. This attack provoked a reprisal, which triggered a general revolt of most of tribes. Attempting to reassert his authority, Amir Khan led a large Mughal Army to the Khyber Pass, where the army was surrounded by tribesmen and routed, with only four men, including the Governor, managing to escape. Aurangzeb's incursions into the Pashtun areas were described by Khushal Khan Khattak as "Black is the Mughal's heart towards all of us Pathans". Aurangzeb employed the scorched earth policy, sending soldiers who massacred, looted and burnt many villages. Aurangzeb also proceeded to use bribery to turn the Pashtun tribes against each other, with the aim that they would distract a unified Pashtun challenge to Mughal authority, and the impact of this was to leave a lasting legacy of mistrust among the tribes. After that the revolt spread, with the Mughals suffering a near total collapse of their authority in the Pashtun belt. The closure of the important Attock-Kabul trade route along the Grand Trunk road was particularly disastrous. By 1674, the situation had deteriorated to a point where Aurangzeb camped at Attock to personally take charge. Switching to diplomacy and bribery along with force of arms, the Mughals eventually split the rebels and partially suppressed the revolt, although they never managed to wield effective authority outside the main trade route. Death By 1689, the conquest of Golconda, Mughal victories in the south expanded the Mughal Empire to 4 million square kilometres, with a population estimated to be over 158 million. But this supremacy was short-lived. Jos Gommans, Professor of Colonial and Global History at the University of Leiden, says that "... the highpoint of imperial centralisation under emperor Aurangzeb coincided with the start of the imperial downfall." Aurangzeb constructed a small marble mosque known as the Moti Masjid (Pearl Mosque) in the Red Fort complex in Delhi. However,