The history of Bandra Fort dates back to the Portuguese, who had established a base in the area in 1534 after defeating Bahadur Shah of Gujarat and built several sea forts along the western Indian coastline. Castella de Aguada was one such strategically located fort, overlooking Mahim Bay to the south, the Arabian Sea to the west, the islands of Worli to the south and the town of Mahim to the southwest. The fort also guarded the northern sea route into Mumbai Harbour. During Portuguese rule, it was armed with seven cannons and other smaller guns as defence. A freshwater spring in the vicinity supplied potable water to passing ships, thus lending the fort its name.