The empire went into decline thereafter. The Mughals suffered several blows due to invasions from Marathas and Afghans. During the decline of the Mughal Empire, several smaller states rose to fill the power vacuum and themselves were contributing factors to the decline. In 1737, the Maratha general Bajirao of the Maratha Empire invaded and plundered Delhi. Under the general Amir Khan Umrao Al Udat, the Mughal Emperor sent 8,000 troops to drive away the 5,000 Maratha cavalry soldiers. Baji Rao, however, easily routed the novice Mughal general and the rest of the imperial Mughal army fled. In 1737, in the final defeat of Mughal Empire, the commander-in-chief of the Mughal Army, Nizam-ul-mulk, was routed at Bhopal by the Maratha army. This essentially brought an end to the Mughal Empire. In 1739, Nader Shah, emperor of Iran, defeated the Mughal army at the Battle of Karnal. After this victory, Nader captured and sacked Delhi, carrying away many treasures, including the Peacock Throne. The Mughal dynasty was reduced to puppet rulers by 1757. The remnants of the Mughal dynasty were finally defeated during the Indian Rebellion of 1857, also called the 1857 War of Independence, and the remains of the empire were formally taken over by the British while the Government of India Act 1858 let the British Crown assume direct control of India in the form of the new British Raj.