Mostly dating from the period 880-612 BC, these carved scenes are found on free-standing stelae and as panels cut on cliffs and rocks at distant places reached by the Assyrian kings during their campaigns. The most spectacular use of stone reliefs, however, was as panels which decorated the mud-brick walls in palaces and temples up to a height of 2.6 metres. The scenes were originally picked out with paint, which occasionally survives, and work like modern comic books, starting the story at one end and following it along the walls to the conclusion.
The Assyrians used a form of gypsum for the reliefs and carved it using iron and copper tools. The stone is easily eroded when exposed to wind and rain and when it was used outside, the reliefs are presumed to have been protected by varnish or paint. It is possible that this form of decoration was adopted by Assyrian kings following their campaigns to the west, where stone reliefs were used in Neo-Hittite cities like Carchemish. The Assyrian reliefs were part of a wider decorative scheme which also included wall paintings and glazed bricks.
The reliefs were first used extensively by king Ashurnasirpal II (about 883-859 BC) at Kalhu (Nimrud). This tradition was maintained in the royal buildings in the later capital cities of Khorsabad and Nineveh.