Blue made of glass
A glaze is glass fused to a ceramic surface, the same thing that makes a mug shiny. Babylon’s brickmakers shaped and dried the bricks, coated them with a mixture that melts into glass when fired, and fired them again so that the coating fused to the clay. The colour isn’t sitting on the surface like paint. It is trapped inside the glass.
Which colour depends on the metal in the mix. In 2019 a team led by Alexandra Rodler analysed the Babylonian glazes and found that the deep blue was made with cobalt, and that Neo-Babylonian craftsmen were among the first to use cobalt in glaze this way. Other glazes in yellow, white, brown and a turquoise green picked out the animals and borders.
Why go to all that trouble? On an outdoor wall, paint fades in sun and washes away in rain, while glass shrugs off both. The blue stays deep, and the glossy surface catches the light, so the wall seems to glow at sunrise or by torchlight.
A city’s worth of kilns
Covering a gate and a long street in glazed brick took serious organisation. Bricks came in standard sizes. Those that carried part of an animal were pressed into moulds, so the same body, mane or hoof could be repeated, which is why the animals look so regular. Each one then went into the kiln a second time, hot enough to melt the glaze without warping the brick.
Every animal is spread over many bricks, laid in courses like any other wall, with the joints running straight through bodies and tails. From a distance the wall reads as one blue field with pale animals walking across it. It looks like lapis lazuli, the precious blue stone Mesopotamia imported from Afghanistan, but not a crumb of it was used.
Who walks on the blue?
The blue is a stage, and each animal on it belongs to a god. The gate carries aurochs, wild bulls sacred to Adad, god of storms, and mušḫuššu dragons, the animal of Marduk, chief god of Babylon. Along the Processional Way leading to the gate walked about 120 lions of the Processional Way, the animal of Ishtar.
At the New Year festival the statues of the gods were carried along that road, through the gate and on towards Marduk’s temple and Babylon’s great ziggurat. Animals at the same height and pace, the shine of the glaze and the sheer size of the gate set the mood of the crowd, and visitors went on describing Babylon’s splendour long after its fall, from the walls to the Hanging Gardens.
Babylon in Berlin
German excavators led by Robert Koldewey, at Babylon from 1899, recovered huge numbers of glazed fragments. In Berlin, conservators sorted them and rebuilt the gate and a narrowed stretch of the Processional Way, filling the gaps with new bricks. What you see there is only part of the original. The Ishtar Gate was a double gate, and the museum could fit only the smaller front section, about 15 m high; the larger rear gate was too big for the building and stayed in storage.
The reconstruction stands in the south wing of the Pergamonmuseum, which stays closed for renovation after the rest of the building reopens on 4 June 2027; press reports suggest around 2037 for the south wing. Panels from the gate and the Processional Way are also in New York, Chicago, Paris and Istanbul, among other cities.
Where to see it
Until the Berlin wing reopens, the easiest way to see the glaze up close is through the lion and dragon panels lent or given to other museums, such as the Metropolitan Museum in New York and the ISAC Museum in Chicago. In Babylon itself, a UNESCO World Heritage Site since 2019, the gate’s foundations are still in place. Check each museum’s website for what is on display.
Sources
- A. S. Rodler, S. Klein, G. Artioli and C. Brøns, “Probing the provenance of archaeological glaze colorants: polychrome faunal reliefs of the Ishtar Gate and the Processional Way of Babylon”, Archaeometry 61.4 (2019).
- A. Fügert and H. Gries (eds.), Glazed Brick Decoration in the Ancient Near East (2020).
- Staatliche Museen zu Berlin, “From Fragment to Monument: The Ishtar Gate in Berlin”.
- Stiftung Preußischer Kulturbesitz, press release on the Pergamonmuseum (4 December 2025).
- The Metropolitan Museum of Art, “Panel with striding lion” (31.13.1, 31.13.2).
- UNESCO World Heritage Centre, “Babylon” (2019).
