See also information on this cycle as part of the Gaspar van Weerbeke Project.
Incipit of the hymn Fit porta Christi pervia omni (Cantus ID 008305c) quoted in S, T and B (openings):
1--gg---d--g---g---ghg---ge---fg---g---4
"Fit porta Christi pervia" (http://cantus.uwaterloo.ca/chant/493424)
See also the Gaspar van Weerbeke Project.