of 1296 and 1297 he was named “master of theology’ in Paris, where he taught up to around 1300 (Teske 2008). Theodoric became one of the two Germans - the other being Abertus Magnus) - to earn this title of magister in the thirteenth century. Theodoric was also present for the general chapter of the Dominican order at Toulouse and his name appears in the general chapter of the order in Piacenza. The last position Theodoric was appointed to was Vicar provincial of Germany in 1310 (Gillispie 2008). His name does not appear in any kind of document after this time. Physics While 13th century authors failed to provide an accurate explanation for the rainbow, at the turn of the fourteenth century Theodoric was able to give one of the first correct geometrical analyses of this phenomenon, which was "probably the most dramatic development of 14th- and 15th-century optics". Drawing from his two earlier works on light and colour, he wrote De iride et radialibus impressionibus (On the Rainbow and the impressions created by irradiance, c. 1304-1311), relying on geometry, experiment, falsification and other methods. Among other properties he explained in detail: the colors of the primary and secondary rainbows the positions of the primary and secondary rainbows the path of sunlight within a drop: light beams are refracted when entering the atmospheric droplets, then reflected inside the droplets and finally refracted again when leaving them. the formation of the rainbow: he explains the role of the individual drops in creating the rainbow the phenomenon of color reversal in the secondary rainbow Using spherical flasks and glass globes filled with water, Theodoric was able to simulate the water droplets during rainfall. Still in its early stages, experimental instrumentation would later expand to be used primarily for making measurements, extending the human senses and creating and isolated environment for the experimenter. During his experimentation with these glass globes, he was correct in asserting that the colors formed by the interaction of sunlight with the water droplets. Recently, scientists have found evidence of the experimental instrumentation used by him. Currently on loan to universities in Providence, Rhode Island, the instrumentation does, indeed, simulate a droplet of water by which sunlight is reflected and refracted, thereby creating a rainbow. He studied refraction and reflection using transparent and opaque bodies (e.g. magnifying glasses, plane, convex and concave mirrors, prisms, and transparent crystal spheres and