<P> Bombay, now called Mumbai, Bombaim in Portuguese, is the financial and commercial capital of India and one of the most populous cities in the world . At the time of arrival of the Portuguese, current Bombay was an archipelago of seven islands . Between the third century BCE and 1348, the islands came under the control of successive Hindu dynasties . The Muslim rulers of Gujarat, who had been ruling current Thane and Vasai for a few decades, annexed the islands in 1348, that were later governed by the Gujarat Sultanate from 1391 to 1534 . Growing apprehensive of the power of the Mughal emperor Humayun, Sultan Bahadur Shah of the Gujarat Sultanate was obliged to sign the Treaty of Bassein with the Portuguese Empire on 23 December 1534 . According to the treaty, the seven islands of Bombay, the nearby strategic town of Bassein and its dependencies were offered to the Portuguese . The territories were later surrendered on 25 October 1535 . </P> <P> The Portuguese were actively involved in the foundation and growth of their Roman Catholic religious orders in Bombay . They called the islands by various names, which finally took the written form Bombaim . The islands were leased to several Portuguese officers during their regime . The Portuguese Franciscans and Jesuits built several churches in the city, prominent being the St. Michael's Church at Mahim, St. John the Baptist Church at Andheri, St. Andrew's Church at Bandra, and Gloria Church at Byculla . The Portuguese also built several fortifications around the city like the Bombay Castle, Castella de Aguada (Castelo da Aguada or Bandra Fort), and Madh Fort . The British were in constant struggle with the Portuguese vying for hegemony over Bombay, as they recognized its strategic natural harbour and its natural isolation from land - attacks . </P>

By what name did the portuguese call the region that we now know as mumbai