In the late 3rd century, it is likely that the army suffered a sharp decline in numbers due to the so-called "Third Century Crisis" (235-70) a period of numerous civil wars, major barbarian invasions and above all, the Plague of Cyprian, an outbreak of smallpox which may have eliminated as many as a third of the army's effectives. It is possible that, by AD 270, the army was not much greater than in AD 24. From this low point it seems that numbers were substantially increased, by at least a third, under Diocletian (r. 284-305): John the Lydian reports at some point in his reign the army totalled 389,704 men – restoring overall strength to the level attained under Hadrian.