ABSTRACT
Although hitherto known as Jacobus Leodiensis, Jacques de Liège, Jacobus de Montibus, the identity of the author of the longest, most systematically organised, and most learned music treatise of the Middle Ages is still unresolved. Some earlier hypotheses acquired the status of fact simply from the absence of competing evidence. The only thing we knew with any certainty about the author of the Speculum musicae was that, as he tells us at the end of the proemium, the initial letters of the seven books spell his name: https://www.niso.org/standards/z39-96/ns/oasis-exchange/table"> Si cui autem huius operis compilatoris nomen scire placet, librorum septem partialium litteras simul iungat capitales. [J A C O B U S] If, however, anyone wishes to know the name of the compiler of this work, let him take together the initial letters of the seven component books. [JACOBUS] Explicit proemium in libro, qui intitulatur speculum musicae. Here ends the prologue to the book called Speculum musicae. 1
