In 1588, the first missionaries from the Society of Jesus arrived in Asunción at the invitation of the settlers and the governor. They set to work at converting the Indians in the area. They also built a prominent church and college; the college was the only educational institution of any importance in the province. The Jesuits gathered a large number of Indians under their care, where they were able to go about Christianizing them and introducing the Indians to elements of Spanish civilization. Most importantly, the Jesuits were able to offer Indians under their care a measure of protection against other whites. Indians on their mission would not be sold into slavery, tricked out of their goods, or have their women taken for extra wives. Over time, an entire "empire within an empire" was built up, and the Jesuits took on responsibilities far beyond religious education. In order to pay royal taxes for the Indians, the Jesuits ran an economy and sold goods at market. In order to defend against Portuguese slavers and hostile Indians, the Jesuits gathered armaments and trained in the arts of war. This arming was highly controversial and was opposed by the Paraguayan settlers, but the constant threat of Portuguese invasion meant the Spanish Crown gave its consent.