Bombay, also called Bom Bahia or Bom Baim in Indo-Portuguese creole, Mumbai in the local language; is the financial and commercial capital of India and one of the most populous cities in the world. It's also the cosmopolitan city centre of the Greater Bombay Metropolitan Area, and the cultural base of the Bollywood film industry. At the time of arrival of the Portuguese Armadas, 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 Delhi Sultanate had been ruling the area along with Chaul, New Bombay (Thana) & Damaon, with the administrative centre in Bassein (Vasai) since the raids of Malik Kafur in the Konkan region and across the Indian subcontinent. This territory in North Konkan along with the Bombay islands were later taken over by the Sultan of Guzerat from 1391 to 1534, when he had declared the end of the suzerainty to Delhi, after the Timurid invasion of it. Growing apprehensive of the power of the Moghal emperor Humayun, Sultan Bahadur Shah of Gujarat was obliged to sign the Treaty of Bassein on 23 December 1534; according to which, the seven islands of Bombay, Fort San Sebastian of Bassein in strategic town of Bassein (Vasai), and its dependencies were offered to the Portuguese East Indies. The places were only later officially surrendered on 25 October 1535, by the Sultan of Guzerat.

The Portuguese Indian Armadas were the fleets of ships funded by the Crown of Portugal, and dispatched on an annual basis from Portugal to India. The principal destination was Goa, and previously Cochin. These armadas undertook the Carreira da Índia from Portugal, following the maritime discovery of the Cape route, to the Indian subcontinent by Vasco da Gama in 1497–99.