These are from a royal building in Balawat, a small town north-east of Nimrud, probably
the temple of the god Mamul, the god of dreams.
The main display is a modern full scale reconstruction of the gates. They stand 6.8 metres high. The originals were made of wood with strips of embossed bronze showing detailed scenes of Shalmaneser’s campaigns. The original bronze strips are displayed to the left. The gates were not hinged, but attached to vertical posts that turned on pivot-stones. These were built by Shalmaneser III in 845 BC - the time of Ahab and Jehu.
British Museum Link