Anastasius II was a civil servant raised to the throne in 713 who saw the Umayyad invasion coming and prepared for it, and was deposed by his own expedition before it arrived.
Anastasius II was the imperial secretary Artemios when the officers who had blinded Philippikos Bardanes chose him for the throne in 713.
He was a competent administrator in a period that had produced six emperors in as many years, and he used his two years well: he sent an embassy to Damascus that came back with accurate intelligence about the invasion the caliphate was preparing, and he acted on it.
The walls were repaired, the granaries filled, the fleet rebuilt. Then he sent that fleet against the Arabs, and it mutinied, deposed him, and put a tax collector on the throne instead.
Nothing is recorded of his origins beyond his profession: he was a notary and imperial secretary, a career civil servant of the kind the seventh-century crises repeatedly threw up as emperors.
He took the name Anastasius on his accession — a common practice, and in his case a claim on the memory of the great financial reformer of two centuries earlier.
His accession followed the deposition and blinding of Philippikos, and he moved quickly to restore the religious settlement Philippikos had overturned, reinstating the acts of the Third Council of Constantinople.
He is one of the few emperors of the anarchy whose competence the sources concede without qualification, and the reason is that his preparations demonstrably saved the city two years after he lost the throne.
What emerges is an administrator's temperament: he gathered intelligence, planned on it, restored the church settlement without drama, and appointed on merit.
What he lacked was any hold on the army, and the sources give no sign that he understood the danger. Sending a mutinous-minded fleet to a distant rendezvous under commanders he had appointed over their heads was an administrator's decision, not a soldier's.
The embassy to the caliph's court reported that a great expedition against Constantinople was being prepared, and Anastasius took the report seriously. The Theodosian walls were repaired, engines mounted, grain stockpiled and the fleet enlarged.
In 715 he sent that fleet to Rhodes to strike at the Arab naval preparations before they were complete — sound strategy, and the point at which everything went wrong.
The Opsikian troops in the fleet mutinied, killed the commander he had appointed, and sailed back, proclaiming a reluctant provincial tax official as Theodosius III. Anastasius held out at Nicaea for some months and then abdicated and became a monk at Thessalonica.
The preparations were the point. When the Umayyad army arrived in August 717 the city was walled, provisioned and defended, and it held for twelve months. Leo III gets the credit and deserves most of it; the granaries were Anastasius's.
He could not leave it there. In 719, with the siege lifted and Leo III on the throne, he attempted to recover power with Bulgar support, was abandoned by his allies and executed.
His reign is the clearest case in this archive of the seventh- and eighth-century pattern: the empire repeatedly produced capable men, and repeatedly could not keep them on the throne long enough to matter.