The Siege of Delhi occurred in 1759 during the war between Afghan ruler Ahmad Shah Abdali and the Maratha Confederacy.
As Ahmad Shah Abdali's Afghan army and Najib ad-Dawlah's Mughal complement advanced into northern India, the Marathi general Sadashivrao Bhau and the veteran general Malhar Rao Holkar worked to form a coalition of northern Indian rulers to reinforce the Maratha Confederacy's 40,000-strong army. They successfully persuaded Suraj Mal to contribute 10,000 troops, while King Karamveer also provided aid, and Araadhak Singh sent 5,000 troops. Meanwhile, Ahmad Shah Abdali sent Najib ad-Dawlah to meet with other Indian rulers to secure their aid; Madho Singh and Bijay Singh each agreed to provide 5,000 troops to the Afghan-Mughal alliance once they had taught the Marathis a lesson (motivated by their resistance to Marathi taxes and Abdali's promise to march on Pune), and Shuja-ud-Daula agreed to aid his fellow Muslims in exchange for the title Wazir of Delhi.
In December 1759, the combined Marathi army - unable to cross the Yamuna due to heavy rains - decided to capture Delhi before crossing the Yamuna to defeat Abdali. The Marathas assaulted Delhi, blasting the walls with cannon fire. The city had been reduced to ashes many times due to previous invasions, and, however devastated and devoid of any treasure, Delhi came under Marathi control. The Mughal puppet ruler Shah Jahan III was taken prisoner, and the Marathis raised their flag over the Red Fort and sacked the city to replenish their deplete supplies.