Complex sentence: There Willekens was revealed that his objective was the capture of the city of Salvador da Bahia, on the coast of Brazil, in order to use its port as a commercial base to ensure the Dutch trade with the East Indies.
Split into simpler sentences: There Willekens was revealed that his objective was the capture of the city of Salvador da Bahia on the coast of Brazil. The main objective of the expedition was the capture of the port to use it as a commercial base to ensure the Dutch trade with the East Indies.