The largest surviving collections of namburbi texts come from the Neo-Assyrian royal court of the seventh century BCE, where scholars in the king's service reported omens by letter almost daily and a namburbi stood ready as the answer to nearly any of them. Because the king's safety was treated as the safety of the state, the correspondence between Assyrian kings and their diviners, much of it recovered from the same Nineveh libraries that preserved Maqlu, shows namburbi rituals being commissioned, scheduled and reported on as routine administrative business rather than emergency measures.
Several hundred distinct namburbi texts are known today, enough that scholars have organized them by the type of omen each answers, lunar eclipses, unusual births, insect infestations, and even accidental encounters with taboo animals. The sheer number reflects how thoroughly omen based anxiety pervaded Mesopotamian court life, and how completely the namburbi ritual class was built to answer it, offering a specific, learnable countermeasure for nearly every variety of inauspicious sign the diviners of the age had catalogued. Some namburbi texts specify substitute figures, a captured animal or even a condemned criminal, standing in for the king himself as the object onto which the portended evil was formally transferred and then destroyed in the king's place.