The Dutch contingent was initially composed mostly of soldiers, with some slaves and other workers from the other Dutch colonies, particularly the area around Batavia (current day Jakarta). The number of soldiers stationed on the island waxed and waned according to the military needs of the colony, from a low of 180 troops in the early days to a high of 1,800 shortly before Koxinga's invasion. There were also a number of other personnel, from traders and merchants to missionaries and schoolteachers, plus the Dutch brought with them slaves from their other colonies, who mainly served as personal slaves for important Dutch people.