were usually excluded from power and from marriage; and, as the daughters of an emperor who had sons had been excluded from marriage since Theodosius' time, collateral branches, and therefore disputed successions, were avoided; but on the other hand a lasting hereditary succession was made impossible, and the crown lay open to any ambitious man or any nominee of the army — a state of affairs which continued till the system was abolished by the Comneni.
Having thus cleared the way, Constantine in 685[1] crowned Justinian as Augustus, but avoided his father's mistake of also crowning his other son, Heraclius. It was nearly his last act: at the beginning of September he died of dysentery, and the boy Justinian became sole emperor.
Constantine had taken advantage of the anarchy which followed the death of the Caliph Yazīd (683) to renew the war; and Melitene was destroyed by the Romans, and the Arabs forced to abandon Germanicea. Hence 'Abd-al-Malik on succeeding his father, Marwān, as Caliph in Syria, was compelled to renew the peace by paying a larger tribute (7 July 685). Nevertheless the new Emperor not only sent an army under the Isaurian Leontius to Armenia and the adjacent countries as far as the Caucasus, which, having seceded from the Arabs, had been invaded by the Chazars (687), but sent another to co-operate with the Mardaites in Syria, and Antioch was occupied (688) for a time. Upon this 'Abd-al-Malik, not even yet being in a position to carry on war, again asked for terms, and a truce was made for ten years on the conditions that he should pay the same tribute as before, that Armenia, Iberia, Arzanene, and Atropatene should be ceded, and the tribute of Cyprus divided, and that Justinian should transfer the Mardaites to his own dominions (689). The Emperor then went to Armenia where he appointed chiefs, took hostages, and received 12,000 Mardaites, whom he settled in different parts of the empire (690). By this step his forces were increased; but the Mardaites would perhaps have been of more use to him in the Caliph's territories.
Justinian had been willing to make peace because he had become involved in a war with the Bulgarians, in which he suffered a defeat (689). During this war however he reduced large numbers of Slavs, whom he settled in the north-west of Asia Minor and organised as a military force under the name of "peculiar people" (λαὸς περιούσιος):[2] this force is said to have amounted to 30,000 men.
Having made peace with the Bulgarians and strengthened the offensive power of the Empire by the acquisition of Mardaites and Slavs, he sought an opportunity of breaking the peace with the Arabs. He began by a breach of the spirit of the compact by which the tribute of Cyprus had been divided; for he removed a large proportion of the population to
