Nadir Shah’s invasion of India left the most tumultuous and destructive mark on the Mughal history of India. He invaded India in 1739. Nadir Shah known for his brutal and inhumane behavior inflicted irretrievable damage to Mughal rule. This invasion is marked as one of the colossal calamities of the period. The power of Mughals was declining at that time and the central power had no control over far flung provinces, which made foreign invasions easy for the enemies of Mughal rulers. Nadir shah became ruler of Persia when Shah Tahmasp last ruler of Safwid dynasty died in 1736. Since Nadir Shah belonged to Afshar tribe of Khusrasan laid the foundation of Afsharid dynasty when his rule as a king started in Persia. Before Nadir Shah got ascended to the thrown he captured and influenced many regions near to Mughal and Safwid sphere of influence. The diplomatic relations between Mughal and Safwid empires started deteriorating at the time Nadir Shah got ascended to the throne. Mughal emperor stopped exchange of ambassadors with Persian court which was considered as a great insult by Nadir Shah.
After Nadir Shah’s accession to the throne he abandoned his conquests of Turks and Russians and got interested in Mughal provinces of Qandahar and Kabul. On 24th of March 1738 he recovered Qandahar, and then he advanced towards Ghazni and Kabul. Muhammad Shah was ruling Delhi when Nadir shah started advancing towards India; Mughal administration was very meager and languid at that time. Another event which compelled Nadir Shah to invade India was that emperor of India refused to return the fugitives who took refuge in Mughal Empire. All of these things were considered as insults so in order to take revenge from Mughal authorities first of all he attacked Lahore by crossing Indus River at point of Attock. After capturing Lahore he started to advance towards Delhi which was the centre of Mughal power at that time.
The purpose of Nadir shah’s invasion is composed of two dimensional aspects first is to take revenge of insults inflicted by Mughals and second because of his ambitions, he was told about the wealth of India which excited him and made him to attack India. On 16th February 1739 he reached Sarhind whereas in a response to his invasions Muhammad shah reached Karnal with 80,000 army men. He was first offered an indemnity of 20 million rupees but the internal enemies of Mughal government told Nadir Shah not to accept this amount because it was very low. After that he denied and battle of Karnal was fought between Nadir Shah and Mughal forces.
Battle took place on 24th of February 1739 it lasted only for three hours because of weak Mughal forces which were not able to stand against massive force of Nadir Shah’s army. After defeating Mughals convincingly on 12th of March 1739 he entered Delhi. He was warmly welcomed by Muhammad Shah who was allowed to retain throne by consent of Nadir shah. At that time conflict arose between Persian soldiers and citizens of Delhi, this was the time when the news of death of Nadir shah also broke out. This thing caused death of many Persian soldiers and when Nadir shah saw bodies of Persian soldiers he ordered full massacre of Delhi, which was then known as notorious Qatal-e-am. He killed 20,000 to 30,000 citizens (men, women, and children) of Delhi in about 6 hours. Whole city was destroyed and made ruin by Persian army; it was a demonstration of brutality and most inhumane treatment ever witnessed by the history of India. Similarly Delhi was looted and plundered by Nadir shah and his army at that level that after Nadir shah’s invasion and sack of Delhi left Mughal Empire so weak and meager that Mughals were not able to regain their strength and fight against other enemies.