The coast of Bassein was first visited by the Portuguese in 1509. Portuguese mariners , discovered the Arab Sultanate of Khambat or Cambay  renovating the fort and attacked it but failed to seize it. Later on 23 December 1534 theTreaty of Bassein was signed by Sultan Bahadur of Gujarat and the Kingdom of Portugal and the Portuguese gained control of the city of Bassein, islands, and seas. 

Bassein was the northern capital of Portuguese till Chimnaji Appa, captured it in 1739in the First Anglo-Maratha War.