Tropical jungle is hostile and impenetrable as well as European settlements were exclusively along the waterways. Portuguese expansion generally was east to west, and from the main channel, the Solimões, north and south along the tributaries. The character of the settlements was of three kinds: defense and occupation ("fortes"), economic ("feitorias"), and evangelical ("missões"). The first permanent Portuguese settlements in the region were Itacoatiara 176 km east of Manaus, founded in 1655 by Portuguese Jesuit Padre António Vieira as Mission of Aroaquis on the island of Aibi near the mouth of Lake Arauató, followed by São Gabriel, founded in 1668 as by Franciscan Friar Teodózio Teodósio da Veiga and Captain Pedro da Costa Favela on the Rio Negro, near the mouth of the Rio Aruím. In 1761, a fort was built on the location, and the settlement became the town of São Gabriel da Cachoeira. The first missionary "aldea" of the Portuguese in the Negro was that known as Santo Elias dos Tarumas (originally aldeia of Nossa Senhora da Conceição, and later called Airão), dating from 1692.