 Ordained a priest sometime during the 1430s, Nicholas first gained wider notice for his work as a conciliarist at the Council of Basel. There he wrote De concordantia catholica (1433), arguing for the authority of the council over that of the pope and stressing the notions of consent and representation. After the turmoil at Basel split the council, Nicholas ultimately sided with the papal party and left the conciliarists. In 1437 he was part of an embassy sent to Constantinople to seek reconciliation of the Greek Church with Rome. He reported that, during the voyage home, the insights of De docta ignorantia (1440) came to him as a kind of divine revelation. He continued as a papal legate to Germany from 1438–48. Named cardinal in 1446 by Eugenius IV, Cusanus was elevated to that position in 1448 by Nicholas V and was sent to Germany in 1451 as papal legate to reform the church.