The last book of the Christian Bible, the Revelation of John, closes with a vision: a city coming down from heaven, shining like a precious stone. It is the heavenly Jerusalem, the «holy city», an image of the world renewed at the end of time. What strikes anyone reading chapter 21 is the care with which the text describes its geometry: measurements, numbers, directions, materials. The city of fulfilment is first of all a perfect figure.
A measured city
In the account an angel takes a golden reed to measure the city, its gates and its walls. The gesture is not new: in the last chapters of his book the prophet Ezekiel had already seen a man measuring a future temple and its city with a reed. In biblical tradition, to measure means to know, to delimit and to consecrate.
The text of Revelation provides precise data:
| Element | Description |
|---|---|
| Shape | the city lies foursquare, its length as great as its breadth |
| Size | twelve thousand stadia; length, breadth and height are equal |
| Walls | one hundred and forty-four cubits |
| Gates | twelve, three on each side, bearing the names of the twelve tribes of Israel |
| Foundations | twelve, bearing the names of the twelve apostles |
| Materials | pure gold like clear glass, gates of pearl, foundations of precious stones |
The square and the cube
The city is described as square in plan, but the text adds that its height equals its length and breadth. In geometric terms, then, it is a cube. The link with the Holy of Holies of Solomon's Temple, which the First Book of Kings describes as a cube, is clear: what was once a hidden room, accessible to one person alone, now becomes an entire city open to all the righteous.
The text says so explicitly: there is no temple in the city, because its temple is God himself and the Lamb. The city needs neither sun nor moon, because the divine glory gives it light. The sacred centre is no longer a place within space: it is the whole of space.
The number twelve
The heavenly Jerusalem is built on twelve and its multiples:
- twelve gates, each guarded by an angel;
- twelve foundations, each adorned with a different precious stone;
- twelve thousand stadia in measure, that is twelve times a thousand;
- one hundred and forty-four cubits for the walls, that is twelve times twelve.
Twelve unites the twelve tribes of the Old Testament and the twelve apostles of the New: the city is the synthesis of the whole history of salvation. But the number also has a geometric and cosmic value: there are twelve months in the year and twelve signs of the zodiac, and twelve is obtained by multiplying four, the number of the earth and the directions, by three, a number often associated with the divine.
The gates, three on each side, repeat this structure in space: towards east, north, south and west. The city is open to every direction of the world.
The twelve stones
The foundations are adorned with twelve precious stones, listed one by one: jasper, sapphire, chalcedony, emerald, sardonyx, carnelian, chrysolite, beryl, topaz, chrysoprase, jacinth and amethyst. The list recalls the stones of the high priest's breastplate described in the Book of Exodus, also twelve in number and linked to the tribes.
In the medieval tradition these lists were commented on at length, each stone being given a spiritual virtue. For sacred geometry one aspect matters above all: the perfect city rests on an ordered base, in which every element has its place and its quality.
Medieval images
The vision of Revelation inspired many works of art and architecture. In the illuminated manuscripts of Beatus of Liébana's commentary on the Apocalypse, the heavenly Jerusalem appears as a large square with twelve arches arranged along its sides, each with the figure of an apostle, and the Lamb at the centre.
Aachen Cathedral preserves the great Barbarossa chandelier, from the twelfth century, a suspended crown of light with towers and gates representing the heavenly city. Many medieval churches too, with their walls, gates and coloured light, were conceived as foretastes of the city to come.
The meaning for the inner path
The heavenly Jerusalem is the point of arrival of a long line of biblical sacred geometry: from the garden of Eden to the tabernacle in the desert, from the Temple to the city. At each step sacred space widens, until it coincides with the renewed world.
Studio Esoterico Cornelio reads this vision as an image of accomplished order: the city is not built to exclude but to welcome from every direction. Its walls define, its gates remain open. This is perhaps the highest lesson of the foursquare city: perfection is not closure, but the harmony of all the parts.
In short
- The heavenly Jerusalem is described in chapter 21 of Revelation as a city coming down from heaven.
- It is a square in plan and a cube in space, with equal length, breadth and height.
- Everything is built on twelve: gates, foundations, apostles, tribes, measurements.
- There is no temple in the city, because the whole of space has become sacred.
- Medieval art depicted it in the Beatus manuscripts and in the Barbarossa chandelier at Aachen.
