The second affair concerned a peace treaty proposed by Krum of Bulgaria (r. 803–814), also in 812, according to which the Byzantine and Bulgarian states should exchange refugees. It is likely that Krum sought the return of certain Bulgarians who had betrayed him to the Byzantines. In this instance Theodore argued against the exchange, as it would require that Christians be cast to barbarians, while Nikephoros urged the emperor to accept the treaty. Once more Theodore's opinion prevailed, although this time with serious consequences; Krum attacked and took Mesembria in November the same year. Michael led a military campaign against the Bulgarians in 813, which ended in defeat, and as a result he abdicated in July and Leo V was crowned emperor.