When Constans' truce with the Arabs ended in 653, however, and a new Arab invasion became likely, Rshtuni voluntarily agreed to submit to Muslim overlordship. In response, Emperor Constans in person led an army of reportedly 100,000 men into Armenia. The local princes rallied to him, and both Armenia and Iberia returned to Byzantine allegiance. After spending the winter in Dvin, Constans left in spring 654. An Arab army invaded and captured the regions on the northern shore of Lake Van soon after. With their assistance, Rshtuni evicted the Byzantine garrisons from Armenia, and secured Arab recognition as presiding prince of Armenia, Iberia, and Albania. The Byzantines under general Maurianos tried to recover control of the region, but without success. In 655, even Byzantine Armenia was invaded, and the Arabs occupied Theodosiopolis (Arabic "Qaliqala") and cemented their control of the country by taking Rhstuni to Damascus, where he died in 656, and appointing his rival Hamazasp Mamikonian in his stead. However, with the outbreak of the First Muslim Civil War in 657, effective Arab authority in the country ceased, and Mamikonian returned to Byzantine overlordship almost immediately.