Historically-informed performance seeks to perform works as accurately as possible to the standards contemporary to when the works were originally composed. However, for medieval and early renaissance music, so little information survives that such interpretations are speculation at best. The gap between what is known and what is performed is of compositional interest to me in many of my works as they explore possible fantasy performances of ancient music as well as draw inspiration from the musical materials and instruments of the period to create uniquely contemporary compositions. This dissertation outlines the process by which I studied the surviving manuscripts to alchemize new works and how ancient aesthetics can be transformed for use in new music.