This most likely author of the Voynich manuscript 
This most likely author of the Voynich manuscript criticized the Julian calendar and recognized the visible spectrum of light in a glass of water. He argued that the external senses serve man in the quest for "illumination," which helps us to recognize "authority," including that of Aquinas, as a source of error. The most famous work of this student of Peregrinus who was at odds with scholasticism was suggested by Clement IV and contains seven parts, including sections on the grammar of science and morality. Called Dr. Mirabilis, for 10 points, name this medieval author of Opus Principale, Opus Majus, and Opus Tertium.
This most likely author of the Voynich manuscript criticized the Julian calendar and recognized the visible spectrum of light in a glass of water.
{R}oger {Bacon}