Son of King Pellinore, Sir Percivale was a knight of the round table who with Sir Bors and Sir Galahad participated on the quest for the Holy Grail. (1)


Percival holds the Holy Grail while a dove descends. (2)

In Arthurian Legend, Percival visits the Grail Castle twice. The first time, he is young and had been taught not to ask unnecessary questions so when he sees the grail he doesn't ask anything and therefore fails. After being enlightened on "The Question" he must ask, he finds the Grail Castle again and achieves the Holy Grail bringing healing to the world and becoming known as the Grail-Knight. (3)


Sources:
(1)http://www.earlybritishkingdoms.com/bios/percivale.html
(2)http://atheism.about.com/od/imagegalleries/ig/Holy-Grail/Percival-holds-the-Holy-Grail.htm
(3)http://www.arthurian-legend.com/more-about/more-about-arthur-5.php