The sigil is only part of Dee's work that has a direct correspondance in earlier magickal systems; versions appear in Liber Juratis and in Eodipus Aegypticus, among other tomes. Dee was intially instructed to copy the sigil from a book in his library, but found conflicting versions and could not decide between them. When he questioned the angels, they proceeded to give him the design for a new, more detailed version.
While most of the names on the sigil are not immediately recognizable, nearly all of them are derived from two sets of fammiliar angelic names. The first set are the angels Agripa lists as "the seven which stand in the presence of God" . The god-names outside the hexagram of the in the Sigil are formed from by the transposition of the letters of these names, following an elaborate but consitant method. The second set are the planetary Archangels, whose names are shown at the center of the Sigil. These are used to form the four groups of seven angelic names within the hexagram, called the "Sons of Light", "Daughters of Light", "Sons of the Sons", and "Daughters of the Daughters.