The device is a piece of European Christian iconography and its setting is the Counter-Reformation. A radiant eye within an equilateral triangle, the triangle for the three persons and the eye for the sight that misses nothing, appears in ceilings, altarpieces, pulpits, tombs and printed title pages across Catholic Europe from the sixteenth century, and passes without friction into Lutheran and Reformed use. Pontormo's Supper at Emmaus of 1525 carries it. It is in the plasterwork of Baroque abbeys, over the doors of parish churches, and it was still being installed in the nineteenth century.
The eye on its own, without the triangle, is older as a figure for divine attention, and the textual warrant is scattered through the Psalms and Proverbs: the eye of the Lord is upon them that fear him; the eyes of the Lord are in every place, beholding the evil and the good. Egyptian, Greek and Roman antiquity have their own eyes of gods and of the sun, none of which is the ancestor of this one along any traceable line, whatever is claimed for the Eye of Horus in popular accounts.
Only the dating matters for what follows. This was ordinary church furniture, in many thousands of buildings, for roughly two hundred years before it appeared on a national emblem or in a Masonic lodge.