Gradually the course of study, at first elementary, embraced the humanities, philosophy, and theology. The religious orders were not impressed, as the Brethren were neither monks nor friars, but they were protected by Popes Eugene IV, Pius II, and Sixtus IV. Cardinal Nicholas of Cusa had been their pupil and so became their staunch protector and benefactor. He was also the patron of Rudolph Agricola (Rudolf de Boer), who in his youth at Zwolle had studied under Thomas à Kempis; and through this connection the Brethren of the Common Life, through Cusa and Agricola, influenced Erasmus and other adepts in the New Learning. More than half of the crowded schools —(in 1500, Deventer had over two thousand students) were swept away in the religious troubles of the sixteenth century. Others languished until the French Revolution, while the rise of universities, the creation of diocesan seminaries, and the competition of new teaching orders gradually extinguished the schools that regarded Deventer and Windesheim as their parent establishments.