And in the spirit he carried me away to a great, high mountain an showed me the holy city of Jersualem coming down out of heaven from God. It was the glory of God and the radiance like a very rare jewel, like jasper, clear as crystal. It has a great, high wall with twelve gates, and at the gates twelve angels. The angel who talked to me had a measuring rod of gold to measure the city and its gates and walls. The wall is built of jasper, while the city is pure gold, clear as glass. The foundations of the wall of the city are adorned with every jewel; the first was jasper, the second sapphire, the third agate, the fourth emerald, the fifth onyx, the sixth carnelian, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, the twelfth amethyst. And the twelve gates are twelve pearls (Rev. 21:10-21)."
An angel grasps John's wrist to pull him up onto the mountain. With a rod crowned with lilies he points to the new, heavenly Jerusalem, represented by a city within an oval wall. The twelve domed towers are arranged in four groups of three. The Lamb of God can be seen inside the city, standing on a sealed scroll.
From the 11th century Bamberg Apocalypse.