As with so much of Spanish history in Late Antiquity, tracing the Justinianic Plague in Spain is a matter of guesswork and extrapolation from a very small body of evidence. The amount of evidence at our disposal has expanded dramatically in recent years because of improvements in the quality and quantity of Spanish archaeological research. Reliable archaeological data is now much more plentiful than is the evidence of more traditional historical sources. One might therefore expect the archaeological record to shed light on plague in sixth-and seventh-century Spain, and it does seem to do so. We must, however, begin from the literary sources for the plague in Spain for a simple methodological reason: Nothing in the material record unambiguously demonstrates the existence of plague in late antique Spain. The literary evidence, by contrast, states explicitly that the peninsula was struck by the plague of 541–543, and that during the next century and a half there were at least three further outbreaks. We must in consequence begin from these explicit attestations of plague and then move on to other sorts of evidence that might bear some relationship to them.

We have only a single literary source for the initial outbreak of the Justinianic Plague in Spain, an anonymous Spanish annotator whose marginal notations are traditionally referred to as the Chronicle of Zaragoza.