The title "Ancient of Days" has been used as a source of inspiration in art and music, denoting the creator's aspects of eternity combined with perfection. William Blake's watercolour relief etching entitled "The Ancient of Days" is one such example.
There are several biblical references for this term, including:
9 "As I looked, thrones were placed, and the Ancient of Days took his seat; his clothing was white as snow, and the hair of his head like pure wool; his throne was fiery flames; its wheels were burning fire. 10 A stream of fire issued and came out from before him; a thousand thousands served him, and ten thousand times ten thousand stood before him; the court sat in judgment, and the books were opened.This term appears three times in the book of Daniel (7:9, 13, 22), and is used in the sense of God being eternal.
—Daniel 7:8-10 ESV)
The most powerful effect of this particular Name of God stems from the Jewish mystical book the Zohar, the seminal document of Kabbalah that stems from 13th century Spain. In the Kaballah there is mention of the Ancient of Ancients, also interpreted as En Sof or the unmanifested God. The Ancient of Days is the maifestation of the Ancient of Ancients in space and time. The Kaballah goes into great detail describing the White Head of God and ultimately the emanation of its personality or attributes.