the cup said to have been used by jesus christ at the last supper; the object of an extended or difficult quest

The holy grail was the cup from which Jesus Christ drank at the time of last supper.

Explanation:

The holy grail is the cup that is to be thought as the cup in which Jesus drank from at the last supper. It is thought to be the cup which was used by Joseph of Arimathea to collect the blood of Jesus Christ during the time of crucifixion.

Because of the facts like this related to it, this object has been a matter of fascination for various years.