Constantes estote videbitis

Source: 
Worcester, Cathedral - Music Library, F.160 (olim 1247) (with hymnal)
Folio: 
012v
Sequence: 
19
Feast: 
Vigilia Nat. Domini
Office/Mass: 
M
Genre: 
R
Position: 
1.2
Cantus ID: 
006328
Mode: 
8
Addendum: 
P: 025