Istorum est*

Source: 
Worcester, Cathedral - Music Library, F.160 (olim 1247) (facsimile)
Folio: 
352
Sequence: 
12
Feast: 
Hippolyti
Office/Mass: 
M
Genre: 
A
Position: 
3.
Cantus ID: 
003451
Mode: 
*
Addendum: 
241r
Manuscript Reading Full Text (standardized spelling): 
Istorum est*
Manuscript Reading Full Text (MS spelling): 
Istorum est