The "Tarikh-i-Firuz Shah" is a historical record written during his reign that attests to the systematic persecution of Hindus under his rule. In particular, it records atrocities on Hindu Brahmin priests who refused to convert to Islam:
An order was accordingly given to the Brahman and was brought before Sultan.The true faith was declared to the Brahman and the right course pointed out. but he refused to accept it. A pile was raised on which the Kaffir with his hands and legs tied was thrown into and the wooden tablet on the top. The pile was lit at two places his head and his feet. The fire first reached him in the feet and drew from him a cry and then fire completely enveloped him. Behold Sultan for his strict adherence to law and rectitude.
Under his rule, Hindus who were forced to pay the mandatory Jizya tax were recorded as infidels, their communities monitored and, if they violated Imperial ordinance and built temples, these were destroyed. In particular, an incident in the village of Gohana in Haryana was recorded in the "Insha-i-Mahry" (another historical record written by Amud Din Abdullah bin Mahru) where Hindus had erected a deity and were arrested, brought to the palace and executed en-masse.
In 1230, the powerful Ganga Vanshi Hindu King of Orissa Anangabhima III consolidated his rule and proclaimed that an attack on Orissa constituted an attack on the king's god. A sign of Anangabhima's determination to protect Hindu culture is the fact that he named his new capital in Cuttack “Abhinava Varanasi.” His anxieties about further Muslim advances in Orissa proved to be well founded. In 1361, the Indian region of Orissa was conquered by the Delhi Sultan Feroz Shah and he destroyed the Jagannath temple and the stone deity of Krishna, but the indigenous wooden image of the deity was saved.
Firoz probably learnt many lessons from his cousin Muhammad's rule. He decided not to reconquer areas that had broken away. He decided to keep nobles and the Ulema happy so that they would allow him to rule his kingdom peacefully. In fact, there were hardly any rebellions during his rule. We come to know about him from a 32-page brochure he wrote. Firoz allowed a noble's son to succeed to his father's position and jagir after his death. The same was done in the army, where an old soldier could send his son, son-in-law or even his slave in his place. He won over the Ulemas by giving them grants of revenue, which gave him political power. He increased the salary of the nobles. He stopped all kinds of harsh punishments such as cutting off hands. Firoz also lowered the land taxes that Muhammad had raised.
He was the first Muslim ruler to think of the material welfare of his people. Many rest houses, gardens and tombs were built. A number of madrasas (Islamic schools which provided Koranic education) were opened to encourage literacy. He set up hospitals for the free treatment of the poor. He provided money for the marriage of girls belonging to poor families. He commissioned many public buildings in Delhi. He built over 300 villages and dug 5 major canals for irrigation bringing more land under cultivation for growing grain and fruit.
Hindu religious works were translated from Sanskrit to Persian. He had a large personal library of manuscripts in Persian, Arabic and other languages. He brought 2 Ashokan Pillars from Meerut and Topara, carefully wrapped in silk, to Delhi. He re-erected one of them in his palace at Firoz Shah Kotla.
He had about 180,000 slaves, who had been brought from all over the country, trained in various arts and crafts. They however turned out to be undependable. Transfer of capital was the highlight of his reign.
Firoz Shah's death led to many rebellions. His lenient attitude had weakened the sultan's position. His successor Ghiyas-ud-Din Tughluq II could not control the slaves or the nobles. The army had become weak. Slowly the empire shrank in size. Ten years after his death, Timur's invasion devastated Delhi.