In Agenda Mortuorum apud Rationale Divinorum by William Durand, Bishop of Mende, 10 October 1477

This seems to be an excerpt from a treatise called Rationale Divinorum Officiorum by William Durand, bishop of Mende (1230-1296), which is about the symbolism of Christian ritual and liturgy and how this relates to Church architecture and art. The excerpt in this manuscript appears to be from Book7, Chapter 35 of the 'Rationale Divinorum Officiorum'('De Officio mortuorum').

It begins, "Hoc loco de officio mortuorum dicendum est..." and ends, "Vir fortissimus Judas Macha. xii, etc. Explicit".