One of the four University of Paris scholars central to the so-called Paris school of physical thought. Evidently from Munster in Westphalia, he was the student of Albert of Saxony (c. 1316-1390), who in turn was a student of the accepted founder of the group, Jean Buridan (c. 1300-c. 1358). Themon followed them with commentaries on Aristotle's physics and the celestial realm. His commentary on the Meteorologica was more substantial than theirs and disagreed with Aristotle that rather than a terrestrial phenomenon, the Milky Way was a heavier portion of celestial space and therefore celestial. He also preserved the basics of Theodoric (or Dietrich) of Freiberg's correct theory of the rainbow.