When was Golconda Fort built?

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 Golkonda from 1512. Their first capital, the fortress citadel of Golkonda, was rebuilt for defense from invading Mughals from the north.