  The central idea of Wyclif's political philosophy is that the dominium defining God's primary relation to creation justifies all human dominium, whether it be the mastery of a king, a lesser civil lord, or a priest. But unlike predecessors who were content to define God's mastery as foundational to human lordship in non-metaphysical terms, Wyclif made ready use of his realist ontology to argue that God's dominium functions as a universal by causality for all instances of just human dominium. For medieval political theorists, this was not common practice; some, like  Aquinas,  can be argued to present unified systems of metaphysics, political thought, and ecclesiology, but many others, including  Ockham,  Marsilius of Padua, John of Paris, and  Giles of Rome,  did not. If, like Ockham or Giles, they had metaphysical positions, it is impossible to argue persuasively that their ontologies affected their politics. This makes Wyclif's political and ecclesiological thought notable, for it is one of the few cases where a distinguished metaphysician used his ontology as a foundation for a detailed examination of the just arrangement of authority in church and state. An immediate corrollary to Wyclif's axiomatic position that all just human dominium derives from God is that no private property relations, which serve as the underpinnings for all human mastery, are just without grace. Because, following  Augustine,  private property is a direct result of the Fall of man, the ideal state is one of communal ownership. Since the Church is the re-established ideal state, grace does not provide for its just ownership of any property whatsoever. Because Wyclif saw the fourteenth-century church enjoying the lion's share of property ownership in England, he argued that the king was bound by God to relieve the church of its property, and to rule over it as a divinely appointed steward. The substance of this argument was realized by Henry VIII, and so Wyclif has been associated, if only as prophetic forerunner, with Tudor reformation. The form of Wyclif's arguments are in no way comparable to modern arguments, though, and are more directly associated with earlier Franciscan positions, like those of  Ockham,  than they are with later political theory. In this essay, the Latin term dominium will be used to distinguish Wyclif's theologically medieval view from its modern English correlate 'dominion', which connotes absolute mastery.