The Mughal emperor who was defeated by the Marathas in the Battle of Panipat was Ahmad Shah Durrani, the founder of the Afghan Durrani Empire.

The Battle of Panipat took place in 1761 between the Maratha Confederacy and the Afghan forces led by Ahmad Shah Durrani. This was the third battle of Panipat, and it is considered a significant turning point in the history of the Mughal Empire.

The key details are:

1. Mughal Emperor: At the time of the Battle of Panipat, the nominal Mughal emperor was Shah Alam II, but the real power was held by the Maratha Confederacy.

2. Maratha Forces: The Maratha forces were led by the Maratha Peshwa Sadashivrao Bhau, who sought to expand Maratha influence and assert control over the declining Mughal Empire.

3. Afghan Forces: The Afghan forces were led by Ahmad Shah Durrani, the founder of the Durrani Empire, who sought to check the growing power of the Marathas and maintain Afghan influence in the region.

4. Outcome: In the fierce battle, the Maratha forces were decisively defeated by the Afghans. This battle weakened the Maratha Confederacy and paved the way for the eventual decline of Mughal power in India.