Overview
Valentinus ( or ; died 644 or 645), sometimes anglicized as Valentine, was a Byzantine usurper of probable Armenian extraction, who served under emperor Constans II from 641 until 644 or 645. He rose to prominence under Heraclius Constantine (Constantine III), who appointed him to secure the succession of his son Heraclius (the later Constans II) to the throne, at the cost of Heraclonas and Martina. Valentinus managed to successfully depose them, along with Heraclonas's brothers David Tiberius and Martinus; this left Constans as sole ruler. Valentinus became the boy's regent, becoming the most powerful man in the empire. Following a failed military campaign against the Arabs, ties between him and Constans became increasingly hostile, such that in 644 or 645, Valentinus attempted to become augustus (emperor) and depose Constans. This failed, and Valentinus was lynched along with his envoy Antoninus.
Biography
According to Sebeos, Valentinus was of Armenian origin, being descended from the royal Arsacid clan. He was initially a member of the retinue of the sakellarios Philagrius, and was tasked in early 641 by Emperor Constantine III (r. February–May 641) to distribute money to the troops in order to secure their loyalty to his infant son Constans, and not the faction of Heraclius's empress-dowager Martina. It is possible that he had been appointed as general or plenipotentiary over the Byzantine army, or that he held the post of comes Obsequii.
In the event, however, on Emperor Constantine's death in May 641, Martina and her son Heraclonas seized power, whilst the loyalists of Constans, most prominently Philagrius, were banished. At this point, Valentinus, who had carried out his assignment and secured the support of the army, led the troops to Chalcedon, across the Bosporus from Constantinople, and demanded that Constans be made co-emperor. Bowing to this pressure, in late September Constans was crowned co-emperor by Heraclonas. In an effort to reduce the importance of this act, however, Heraclonas also had two of his younger brothers, David and Marinus, raised to the rank of augustus and caesar respectively. Valentinus himself was "rewarded" by being given the title of comes excubitorum. Nevertheless, according to Sebeos's account, it was Valentinus who engineered the final fall and mutilation of Martina and Heraclonas a few months later, and imposed Constans as sole Byzantine emperor.
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