By the middle decades of the sixth century, economic decline was becoming apparent in the northern Horn, most noticeably in the area around Aksum itself. The overall population of the capital area diminished sharply. Several of Aksum's grand buildings fell into disrepair and were apparently occupied by squatters. Use of the Gobedra quarries to provide the materials for massive masonry came to an abrupt end, to judge from the number of blocks that were abandoned after extraction had begun. The coinage suffered a marked reduction both in technical quality and in metallurgical fineness, accompanied by a proliferation of tiny base-metal issues that may indicate inflation and reduction in living standards. Detailed interpretation of this last point is hindered by continuing uncertainty surrounding the sequence of reigns and coinage issues between the mid-sixth and mid-seventh centuries, as discussed in Chapter 14, but the most likely picture appears to be that debasement of the gold accelerated during the third quarter of the sixth century, followed shortly afterwards by the proliferation of small copper coins.

The expansion of Aksum and its population during the fourth century and – perhaps to a lesser extent – the fifth is indicated by archaeological survey, results obtained by Michels in the 1970s being supported by those of more recent fieldwork based on more precise chronological indicators. This concentration probably resulted in serious depletion of resources, notably timber, accompanied by environmental deterioration. A rapid and pronounced depopulation followed. This may have been partly due to reduced carrying capacity of the local environment, but other factors probably contributed.