Percival is often explained as "pierce the valley," though that reading may be a later poetic gloss rather than the name's true root, which remains genuinely unclear. What has stuck regardless is its association with a knight defined by a long, uncertain search -- a name tied to quest more than arrival.
Make the Sun, or any of the superiors to signify princes and great persons. Scribes and rusticks, [are shown by] the inferior planets, and chiefly the Moon. - William Lilly (1602.-1681.)