Galle was known as Gimhathiththa before the arrival of the Portuguese in the 16th century, when it was the main port on the island. Galle reached the height of its development in the 18th century, during the Dutch colonial period. Galle is the best example of a fortified city built by the Portuguese in South and Southeast Asia, showing the interaction between Portuguese architectural styles and native traditions. The city was extensively fortified by the Dutch during the 17th century from 1649 onwards. The Galle fort is a world heritage site and is the largest remaining fortress in Asia built by European occupiers.