Why four-sided forms keep appearing
Four is the number of the cardinal points, and a square is the simplest figure that can be laid out against them. A builder who marks out north, south, east and west on the ground has already drawn a cross, and joining its four ends gives a square. That practical fact helps explain why the square and the cross turn up in so many unrelated cultures. It is also why their meanings tend to overlap: both were read as images of order, of the earth, and of a place made ready for something sacred.
This article looks at those two forms as they were used in building and ritual, and at what builders and theologians said about them. The wider fourfold schemes of elements, seasons and humours are covered elsewhere, and so is the numerological habit of stressing the stability of four, which is largely a modern reading rather than an ancient one.
The square as ordered ground
In several traditions a sacred site begins with a square, and the square stands for the settled, measured world.
- India. Classical treatises on temple building describe the vastu-purusha mandala, a square grid, often of 64 or 81 cells, laid over the site. Each cell is assigned to a deity or a function, and the temple’s plan follows the grid. The square is meant to hold a cosmic order in a small area.
- Rome. Augurs marked out a rectangle of sky for observation, and Roman towns and military camps were often laid out with two main streets crossing at right angles, dividing the settlement into four quarters. The cross of roads served as a practical frame and a religious one.
- China. A long-standing idea pictured heaven as round and earth as square. The Temple of Heaven complex in Beijing, built in the early fifteenth century and later rebuilt, is often described as expressing this with a round altar and a square enclosure, though the symbolism was expressed in several ways over the centuries.
- Egypt and Mesopotamia. The Great Pyramid has a nearly square base with its sides closely aligned to the cardinal directions. Mesopotamian ziggurats had rectangular or square bases. What the builders themselves wrote about the shape is limited, so interpretations of its meaning vary.
The same impulse appears in the Americas. In some Indigenous traditions the sacred directions and their colours are central, as in the Navajo sacred four directions, and the Inca state was divided into four parts meeting at Cusco. Those are regional systems with their own logic and are not simply versions of one universal symbol.
The cube and the “foursquare” city
When a square is extended upward it becomes a cube, and cubic spaces were treated as especially complete. In the biblical account of Solomon’s Temple, the innermost room, the Holy of Holies, is described as 20 cubits in length, width and height, which makes it a cube. Later readers took the equal dimensions as a sign of perfection and stability.
The book of Revelation describes the new Jerusalem as laid out “foursquare”, with equal length and breadth, and with gates facing each of the four directions. Medieval commentators read the shape as a statement of completeness. The Kaaba in Mecca is a roughly cuboid building, and its Arabic name is often said to be related to the word for cube, although the meaning attached to its shape is mainly religious, not geometric: it marks the orientation of prayer, and the pilgrimage to it is one of the Five Pillars.
The cross and the plan of the church
The cross is older than Christianity as a decorative and cosmic sign. Equal-armed crosses appear in many ancient cultures, often connected with the sun, the directions or the idea of a centre. In Christian use the cross took on its central meaning from the crucifixion, and writers soon began to read its four arms as stretching to the four corners of the world. Some early Christian authors made this point explicitly, presenting the cross as a sign of the universal reach of the faith.
That reading shaped architecture. Churches in the Latin West were often built on a cross-shaped plan, with a long nave, transepts and an apse. Byzantine builders favoured a centralised design with equal arms, the Greek cross, frequently set inside a square, so that a cross and a square were combined in a single plan. A dome over the crossing could be read as heaven above the earthly square. Medieval writers on liturgy, such as Durand in the thirteenth century, listed meanings for almost every part of the building. It is fair to say that these meanings were often added after the fact by commentators, rather than being the reasons builders chose a plan. Structural needs, local custom and cost also mattered, and the details of Christian number symbolism changed from author to author.
Squares in the mandala
Buddhist and Hindu mandalas often place a square, with four gates, inside a circle. The gates face the four directions and the centre holds the principal figure. The square functions as a palace or sacred precinct, the circle as an encompassing field. The pairing of square and circle is also found in European writing, including the Vitruvian idea that human proportions fit both figures, and medieval art sometimes placed the four evangelists at the corners of a framing design.
What the forms did and did not mean
Across these examples a pattern is clear. The square stands for the measured, ordered earth; the cross stands for the meeting of directions and, in Christianity, for a particular event; the cube for completeness. But each tradition supplied its own reasons, and the same shape could carry different messages in different places. To say that the number four itself “causes” anything in a building would go well beyond the evidence. What can be shown is that people used the simplest geometry available to express order, and explained it in the terms of their own beliefs.