Marañón River
In 1637, the Jesuits Gaspar Cugia and Lucas de la Cueva from Quito began establishing the Mainas missions in territories on the banks of the Marañón River, around the Pongo de Manseriche region, close to the Spanish settlement of Borja. Between 1637 and 1652 there were 14 missions established along the Marañón River and its southern tributaries, the Huallaga and the Ucayali rivers. Jesuit Lucas de la Cueva and Raimundo de Santacruz opened up two new routes of communication with Quito, through the Pastaza and Napo rivers.