The slave trade started around 1660. Willemstad became a centre of African slave trading for all of North America, although some of these slaves were also forced to work on the plantations on Curaçao itself. Profits were not gained quickly, however, and it was not until the end of the 17th century that the town started to prosper. This prosperity resulted in the expansion of Willemstad at the end of the 17th or the beginning of the 18th century. The canal between the fort and the settlement was filled in and the rectangular, somewhat fanned out street plan was extended. Many companies, houses and facilities were built in this new town quarter, among which, in ca. 1730, a synagogue, which today is the oldest in the New World.

The oldest part of the town – Punda – initially had a 17th century Dutch character with narrow, multi-storey houses built at right angles to the streets. This part of town gives a planned impression. It was followed by a period in which Baroque influences can be discerned. During the 18th and 19th centuries ‘tropical neoclassicism’ would play a major role; the architectural style merged to ever greater extents with the prevailing architecture of the region, which was mainly rooted in Southern Europe, sometimes resulting in galleries, arcades, porticos and (covered) balconies constructed beyond the original building lines. As of 1817 the buildings were no longer allowed to be painted white because of the bright sunlight, so the outside walls were colour-washed in a variety of soft and bright colours.