The Abbey of Ishap is a temple and research facility in Betrayal at Krondor. It can be visited in Chapter 1.
The Abbey occupies the one-story keep of the former fortress at Sarth. Father John, an aged dark-skinned man with snow-drift hair and beard, is the abbot. Brother Anthony and Brother Marc are involved with the library.
Father John greets the party, accepts their praise of the work the Abbey is doing, and directs them to Brother Marc for more detailed information.
In Chapter 1, the Abbey's mandala is unfinished, precluding any teleportation to or from Sarth.
A book in the Sarth library, one of hundreds about Ishap, calls him the God Above All.
The spell Eyes of Ishap allows the caster to sense vessels in a given area.