During its heyday in the eight and seventh centuries BCE, the Neo-Assyrian Empire was so militarily powerful that few armies could stand against it in open combat. The annual campaigns of the Assyrian monarchs were thus largely occupied with city sieges, memorialized both in royal inscriptions and in the sculptural relief programs that decorated their royal palaces. Imagery of systematic urban destruction was triumphantly presented over and over again in these reliefs, in portrayals no less graphic than the depictions of death and torture which have long made these sculptural narratives notorious. These images testify to the unprecedented violence and technical expertise which the Assyrians brought to sieges: city walls (an important symbol of political independence in the ancient Near East) are seen dismantled, brick by brick, by complex war engines or digging soldiers, and collapsing masonry and falling enemy combatants echo each other’s demise. The walls of the royal palaces were covered by these vivid portrayals of the violent dissolution of city life, a striking fact when considering that these palaces were often situated within capital cities newly built or renovated by the kings themselves. This dissertation explores how the Assyrian state couched this destructive enterprise within the broader concepts of entropy and dissolution inherent in Mesopotamian cosmology. In Assyrian royal inscriptions the actions of king and army are compared to the violence of natural disaster, or equated with the dissolving power of time itself by turning enemy cities into deserted ruins. Within the reliefs, siege depictions consistently focus upon the entropic touch of soldiers’ weapons and siege engines as they dismantled enemy settlements into constituent parts. And within the architectural environs of at least one royal citadel, Sargon II’s palace at Dur Šarruken, siege images were deployed to structure visitors’ experience of physical space, placed at transitional points between rooms and emphasizing choices in directional movement. Ultimately all of these rhetorical approaches, I argue, attempted to place the Assyrian Empire in violent harmony with the forces of dissolution naturally at play in the cosmos, and to shield its own works from their effects.