  Yet Marchia did not come up with the theory of inertia, Buridan’s theory of impetus, or Oresme’s modifications to Buridan’s theory. Part of the reason for this is that Marchia presented his idea in the context of a discussion of the sacraments. This is not unusual for Marchia: in developing his doctrine on the nature of accidents, for example, the Franciscan theologian began with the miracle of the Eucharist and modified Aristotelian metaphysics accordingly (Amerini 2006). Thus for Marchia, projectile motion was just one of many instances where a force was left behind. In essence Marchia wanted a unified theory of virtus derelicta that would explain a number of phenomena, including speaking, seeing, celestial motion, and the conversation of the saints in heaven, in addition to the power of the sacraments and projectile motion. Since some of these phenomena were temporary and not permanent, exhausting themselves without external resistance, Marchia applied this to the general theory: virtus derelicta is a self-expending and therefore temporary force. Accordingly, Marchia believed that celestial motion was probably not perpetual based on an initial virtus derelicta, perhaps left behind by God, although he asserted that it was at least possible that, in the heavens, without resistance, the virtus derelicta could be incorruptible. Making it a permanent force is the step that Buridan would take. But Buridan was not concerned with all those other phenomena. For all we know, Marchia would have approved of Buridan’s notion. As it stands, Marchia’s theory, especially in its particular details, “is neither an Aristotelian solution to the problem of projectile motion nor a new development on the road to early modern science; it belongs to a new (but subsequently undeveloped) understanding of motion” (Zanin 2006b, 81). Nevertheless, if we consider that Marchia appears to have been the first in the West to break with Aristotle so clearly, decisively, and prolixly, it is more than likely that his virtus derelicta was Buridan’s inspiration.