The most important builder of Golconda was Ibrahim Quli Qutb Shah Wali, the fourth Qutb king. Ibrahim was following in the spirit of his ancestors, the Qutub Shahi kings, a great family of builders who had ruled the kingdom of Golconda from 1512. Their first capital, the fortress citadel of Golconda, was rebuilt for defense from invading Mughals from the north. They laid out Golconda's splendid monuments, now in ruins, and designed a perfect acoustical system by which a hand clap sounded at the fort's main gates, the grand portico, was heard at the top of the citadel, situated on a 300-foot (91 m)-high granite hill. This is one of the fascinating features of the fort.