what is the historical origin of the three lesser lights in craft masonry and how did their placement change over time

The origin of three lights surrounding a holy place is traced by Carl H. Claudy to ancient rites such as the Mysteries of Eleusis, where they represented the Sun, Moon, and Mercury 1. In the Craft, these lesser lights represent the Sun, Moon, and Worshipful Master 12.

Regarding their placement, early nineteenth-century records set out their positions in the East, South, and West, with no light placed in the North because the sun casts no rays from below the horizon to that quarter 2. Modern practice maintains the triangular arrangement, though lodges vary in setting them to form a right, equilateral, or isosceles triangle 1.