His chief works are: De conjunctione animae et corporis humani; Exercitationes centum de cognitione Dei nostri; Logica vetus et nova; Initiatio philosophi, seu Dubitatio Cartesiana; a commentary on Descartes' Meditations; and Ars etymologica Teutonum.
About the same time Marsilio completed and published his treatise on the Platonic doctrine of immortality (Theologia Platonica de immortalitate animae), the work by which his claims to take rank as a philosopher must be estimated.
The last reference to him, as living, is in 1208, when an order for payment to him is on record, but Giraldus Cambrensis, in the second edition of his Hibernica, redacted in 1210, utters a prayer for his soul, "cujus animae propitietur Deus," a proof that he was no longer alive.
His only printed works are a fragment on the Eucharist (inserted by Jean Mabillon in his edition of the works of St Bernard), and the Morelia Abbreviata and De Origine Animae (in E.
- To this class belong the Apologeticus (197) and the two books Ad nationes, De spectaculis, De idololatria, De cultu feminarum Libri II., De testimonio animae (written soon after the Apologeticus), Ad.