Sarras is a mystical island to which the Holy Grail is brought in the Arthurian legend.
The party wins many converts, and moves on to Britain where they establish a great line of kings.
After they achieve the Grail the knights Galahad, Percival, and Bors return the object to Sarras aboard Solomon's ship, but they find the residents fallen back to paganism.
The Lancelot-Grail Cycle places Sarras on the road from Jerusalem to the Euphrates and Babylon, and it is considered the origin of the name "Saracens" for Muslims.
In reality "Saracens" was a Greek designation for Arab tribes of the Sinai Desert.