Nizam Shah I was the first sultan of the Nizam Shahi dynasty and built which fort to defend the...........

Explanation:

The fort was built by Malik Ahmad Nizam Shah I (after whom the city of Ahmednagar is named) in 1427. He was the first sultan of the Nizam Shahi dynasty and he built the fort to defend the city against invaders from neighbouring Idar[citation needed] Initially it was made of mud but major fortification began in 1559 under Hussain Nizam Shah. It took four years and was finally finished in 1562.