Mumbai City - India Bombay , now called Mumbai is home to around 10 million people. It is a bustling cosmopolitan, multi-cultural city, and is the centre of India's entertainment industry. Ancient Mumbai Bombay was originally — not one city — but seven separate and amorphous islands separated by swamps: the region was inhospitable to human settlements due to malarial swamps and tropical forests. The Muslim rulers of Gujarat annexed the islands from the local Hindu rulers and governed it from 1391 to 1534. Seven Islands Portoguese Bom Baia The Gujarat Sultanate was obliged to sign the Treaty of Bassein with the Portuguese Empire and the seven islands of Bombay were surrendered to the Portuguese on 25 October 1535. The Portuguese actively engaged in laying the foundation of Roman Catholic religious orders in the islands. They built several catholic churches and establishe a port fro trading with Portugal. The Portuguese called the place Bom Baía , meaning ' The Good Bay '.