Philippe de Vitry’s biggest motet, the 250-breve Petre/Lugentium, got even bigger when a tenor-contratenor voice pair for the motet came to light in a parchment fragment unglued from a binding. Here it is, courtesy of the Stadtbibliothek Aachen, where it lives:
I first ran into this source c. 2013 in a 2001 publication by Joachim Lüdtke. In an article just released online by Early Music (and which you can read for free by following this link—thanks OUP!) I evaluate its significance for our understanding of Vitry, especially of his motets Petre/Lugentium and Phi millies/O creator.
Petre/Lugentium was composed by Vitry in December 1342 in honor of Pierre Roger (1291–1352) in his first year as Pope Clement VI. It is an amazing motet with spectacular hockets, made only more spectacular now by the participation of two lower voices. To supplement the article I have made two new editions of it that incorporate the information that can be gleaned from this badly rubbed but ultimately legible fragment:
–an edition of the original four-voice version of Petre/Lugentium ready to be sung from and taught with, including a new edition and translation of the texts by Zoltàn Rihmer
–a comparative edition of all surviving voices of Petre/Lugentium that includes the original four plus a solus tenor in Aachen and another solus tenor (confusingly labeled “tenor”) in Ivrea
I will post more soon about the issue of Early Music from which this article comes—an issue dedicated to Vitry. For now, I hope you enjoy the newly excavated Petre/Lugentium à 4!
 J. Lüdtke, ‘Kleinüberlieferung mehrstimmiger Musik vor 1550 in deutschem Sprachgebiet IV: Fragmente und versprengte Überlieferung des 14. bis 16. Jahrhunderts aus dem mittleren und nördlichen Deutschland’, Nachrichten der Akademie der Wissenschaften in Göttingen, philologisch-historische Klasse, vi (2001), pp.420–87.