The Vesica Piscis

Documented origin

The vesica piscis is the pointed-oval or “lens” shape formed when two circles of equal radius are placed so that each center sits on the other’s circumference. The intersection yields a figure whose long axis to short axis ratio is √3 — a proportion that generates the equilateral triangle and underlies much of classical sacred architecture. The form was employed as a geometric generator in antiquity and codified as a master proportion by medieval cathedral builders, who used it to establish the proportions of nave, choir, and vault.

The reading

In the sacred geometry tradition, Manly P. Hall reads the vesica piscis as the primordial womb — the portal through which spirit passes to enter matter, the meeting of two perfect circles producing the first differentiated form. Santos Bonacci extends the reading to the Christian fish: the Ichthys symbol is the vesica in outline, and the fish of Pisces is the womb of the astrological age. In this view the most ubiquitous symbol of Christianity is a geometry lesson about the nature of creation.

Where it hides today

Gothic church windows frame their tracery inside it; the mandorla encloses Christ and the Virgin in altarpieces across Europe. The Christian bumper-sticker fish is its simplest trace. Corporate logo designers reach for the overlap without always knowing the name — the almond-shaped intersection marking the place where two things become one.