Shivaji’s first major naval fleet was established at Colaba (Kolaba Fort). Realizing that control over the sea was essential for the survival of his coastal kingdom against the Siddis of Janjira and the Portuguese, Shivaji began naval construction as early as 1657. His navy grew to include various types of fighting vessels and transport ships, making him the only Indian ruler of his time to successfully challenge European and Abyssinian naval powers along the Konkan coast.