what does "abbey" mean in reference to the museum?
It was one in which the abbot was given permission to use pontifical insignia, including the mitre, ring and pontifical staff, and to give the solemn benediction provided a bishop was not present.
Norton Priory
 A mitred abbey was one in which the abbot was given permission to use pontifical insignia, including the mitre, ring and pontifical staff, and to give the solemn benediction provided a bishop was not present. 
what is norton priory? It is a historic site and currently a museum. where did it get its name? UNANSWERABLE
wiki:22336456
Norton Priory [SEP] Abbey
Horseflesh was not eaten. Although few fish bones have been discovered, it is known from documentary evidence that the canons owned a number of local fisheries. The fuel used consisted of wood and charcoal, and turf from marshes over which the priory had rights of turbary (to cut turf).