The Bassein region ruled by Portuguese in not just Bassein but included areas far away as Bombay, Thane, Kalyan and Chaul (Revdanda) (Chaul Fort Photo). It is located about 50 Kilometers North of Bombay, on the Arabian Sea, at approximately (19°20'N - 72°49'E). Bassein, was important trading center, it's sources of wealth and trade were horses, fish, salt, timber, stone quarry (basalt and granite) and shipbuilding. It was a significant trading center long before the Portuguese arrived. (Ancient Sopara was a important port in trade with the Arabs and Greeks, Romans and Persians.). It was also a wealthy agricultural region with rice, betel nut, cotton, and sugar-cane as some of the crops.
The Portuguese with their naval power and their crusading valor were unquestioned masters of the Indian Ocean. When the Portuguese arrived, Bassein was under the rule of Bahadur Shah, the Sultan of Gujarat.
In 1530 Antonio de Sylveria burnt the city of Bassein and continued the burning and looting to nearby Bombay, when the King of Thana surrendered islands of Mahim and Bombay. Subsequently, the towns of Thana,