Why did Desiderius Erasmus leave monastic life after becoming a priest?

Desiderius Erasmus left monastic life primarily because he felt stifled by the environment of the monastery, which he found incompatible with his intellectual pursuits.

While at the monastery of the Augustinian canons at Steyn, Erasmus faced discouragement from his superiors regarding his classical studies. He viewed these superiors as "barbarians" who hindered his scholarly interests. Consequently, following his ordination to the priesthood in April 1492, he welcomed the opportunity to leave the monastery by accepting a position as Latin secretary to the bishop of Cambrai.1

Erasmus’s disillusionment with the cloister deepened over time. He later became a vocal critic of monasticism, famously asserting in his work Enchiridion militis Christiani that "monasticism is not piety." His experiences, including the influence of the preacher Jean Voirier—who described monasticism as a life for "fatuous men"—further solidified his conviction that true religious devotion was not tied to the cloistered life.2