The Javanese cultural mix was further enriched with the spread of Islam in the 15th and 16th centuries. The coastal population and the aristocracy were the first elements to be influenced by the new culture, but by the 16th century the nominally Muslim Mataram Empire had established control over the entire island. Portuguese traders visited the island in the 16th century. Toward the close of that century, Dutch traders ended Portuguese commercial influence on Java. The establishment of Batavia (now Jakarta) in 1619 signaled the birth of the new Dutch empire. The Dutch swiftly enlarged their sphere of influence and by 1755 controlled a large portion of the island. During the Napoleonic Wars, the Dutch administration in Java was manipulated by the French, who at the time occupied the Netherlands. In 1811 the British took over and remained in control of Java until 1816, when the island was restored to Dutch sovereignty. Between 1825 and 1830 Dutch authority in Java was unsuccessfully challenged by a Javanese rebellion. Thereafter, the island remained under the rule of the Netherlands until the Japanese occupation, begun in March 1942, during World War II (1939-1945). Indonesia gained their independance August 17, 1945.