Vesica piscis
Also called mandorla, fish bladder
Euclid’s first construction; the Latin name is later
Geometry symbolsVesica piscis meaning
The vesica piscis is the lens where two equal circles overlap, each passing through the other’s center. Euclid’s first proposition uses that construction. The Christian mandorla is the same shape put around a body.
Two equal circles, each through the other’s center. A third shape appears.
The name. Latin, the bladder of a fish. The almond of overlap is the figure.
Where it comes from
Euclid’s first proposition — the equilateral triangle — is this drawing with the triangle stroked in. The overlap has the height of an equilateral and the irrational √3 in its proportions, which is why medieval masons could lay out a building from two ropes. In Christian art the same almond, the mandorla, surrounds Christ in Majesty. The ichthys association is a rhyme that arrived because both are fish-shaped, not because Euclid was hiding a creed.
Geometry
Relation makes a new thing
Neither circle contains the vesica. It belongs to both and to neither. That is the whole philosophical use of the figure, and it does not require a mystery school. Two equal wholes overlap, and a pointed middle shows up that was not drawn on purpose. Generation, in this lexicon, often looks like that.
Christian
The glory around a body
The mandorla is glory as a boundary: the person inside is in the world and not only in the world. Romanesque portals use it because the shape fits a standing body. Practical and theological at once, which is how a workshop thinks.
Near this
Sources
- Euclid, Elements I.1
- Romanesque mandorlas in Christian art
Named when the entry depends on a text, a date, or a standard. Catalog numbers are not invented.
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symbol.wiki, edited as Sigilla. Last reviewed 2 October 2026. A reading of public tradition, not a ruling.