the sultan had to withdraw the lot, "buying back both the real and the counterfeit at great expense until mountains of coins had accumulated within the walls of Tughluqabad." Muhammad bin Tughlaq planned an attack on Khurasan and Irak (Babylon and Persia) as well as China to bring these regions under Sunni Islam. For Khurasan attack, a cavalry of over 300,000 horses were gathered near Delhi, for a year at state treasury's expense, while spies claiming to be from Khurasan collected rewards for information on how to attack and subdue these lands. However, before he could begin the attack on Persian lands in the second year of preparations, the plunder he had collected from Indian subcontinent had emptied, provinces were too poor to support the large army, and the soldiers refused to remain in his service without pay. For the attack on China, Muhammad bin Tughlaq sent 100,000 soldiers, a part of his army, over the Himalayas. However, Hindus closed the passes through the Himalayas and blocked the passage for retreat. Kangra's Prithvi Chand II defeated the army of Muhammad bin Tughluq which was not able to fight in the hills. Nearly all his 100,000 soldiers perished in 1333 and were forced to retreat. The high mountain weather and lack of retreat destroyed that army in the Himalayas. The few soldiers who returned with bad news were executed under orders of the Sultan. During his reign, state revenues collapsed from his policies. To cover state expenses, Muhammad bin Tughlaq sharply raised taxes on his ever-shrinking empire. Except in times of war, he did not pay his staff from his treasury. Ibn Battuta noted in his memoir that Muhammad bin Tughlaq paid his army, judges (qadi), court advisors, wazirs, governors, district officials and others in his service by awarding them the right to force collect taxes on Hindu villages, keep a portion and transfer rest to his treasury. Those who failed to pay taxes were hunted and executed. Muhammad bin Tughlaq died in March 1351 while trying to chase and punish people for rebellion and their refusal to pay taxes in Sindh (now in Pakistan) and Gujarat (now in India). Historians have attempted to determine the motivations behind Muhammad bin Tughlaq's behavior and his actions. Some state Tughlaq tried to enforce orthodox Islamic observance and practice, promote jihad in South Asia as al-Mujahid fi sabilillah ('Warrior for the Path of God')