What was Opus nonaginta dierum by William of Ockham?

Opus nonaginta dierum (Latin for "Work of 90 Days") is a voluminous political treatise written by the English Franciscan philosopher William of Ockham.

Composed alone by Ockham between 1330 and 1338, the work was written during his period of exile in Munich under the protection of Emperor Louis IV. It serves as a central text in his defense of the strict Franciscan interpretation of poverty. In this work, Ockham argued that Christ and his Apostles had renounced all rights to property and ownership, thereby justifying the Franciscan commitment to a life of absolute poverty. The treatise was part of Ockham's broader intellectual campaign against the papacy of John XXII, whom Ockham accused of heresy for challenging the order's stance on property rights.1