Editing Anastasius II (emperor) (section)

=== Rebellion ===
Theodosius, the reigning emperor, was later deposed by [[Leo III the Isaurian|Leo III]], who had previously served under Anastasius. Leo would face two successive crises during his rule. The first crisis occurred when [[Siege of Constantinople (717–718)|the Umayyad Caliphate besieged Constantinople]], causing confusion about whether the city had been conquered. Troops stationed in Sicily declared their support for a new emperor, mistakenly believing that the capital had fallen.<ref name=":2" /> Although their rebellion was suppressed, the siege and the subsequent rebellion created an appearance of weakness in Leo's new government. Observing this, Anastasius decided to rebel and reclaim the Byzantine throne.

In 719, Anastasius left Thessalonica to lead a revolt against Leo III. The instigator of the rebellion is a matter of debate, with conflicting accounts from [[Nikephoros I of Constantinople|Patriarch Nikephoros]] and Theophanes the Confessor. Nikephoros claims that Anastasius orchestrated the plot himself, while Theophanes suggests that Niketas Xylinites initiated the rebellion by corresponding with Anastasius. Regardless, Anastasius sought support from [[Tervel of Bulgaria]] and received a significant number of troops, as well as financial aid amounting to 50,000 [[litre]]s of gold.<ref name=":2" /> However, Theophanes the Confessor, who provides this information elsewhere, mistakenly confuses Tervel with his eventual successor [[Kormesiy of Bulgaria|Kormesiy]], leaving the possibility that Anastasius formed an alliance with the younger ruler. Another explanation posits that Kormesiy acted as a representative of Tervel during negotiations with Anastasius.<ref name=":4">{{Cite book |last=Sheppard |first=Si |url=https://books.google.com/books?id=HAqlDwAAQBAJ&pg=PT145 |title=Constantinople AD 717–18: The Crucible of History |date=2020-03-19 |publisher=Bloomsbury Publishing |isbn=978-1-4728-3693-9 |language=en}}</ref>

Although the coups during the Twenty Years Anarchy had seen some success, rebellions carried a high risk of failure. Therefore, Anastasius must have had a compelling reason to believe that the risk was worth taking. One explanation is that he interpreted the siege of Constantinople and the minor rebellion as indications of the state's weakness, making him believe that a rebellion could succeed. Another possibility is that Anastasius genuinely believed that the Empire was in a state of crisis and that he was one of the few individuals capable of saving it. Lastly, it is plausible that Theophanes was accurate in asserting that Niketas Xylinites advised Anastasius to rebel.

With the Bulgarian forces by his side, Anastasius marched toward Constantinople. He had sent a message to Niketas Anthrakas, the commander of the city walls, requesting that the gates be opened upon his arrival. Unfortunately for Anastasius, the message was intercepted, leading to Niketas being beheaded and foiling Anastasius' plan to enter Constantinople easily.<ref name=":2" /> Unable to breach the city, Anastasius and his conspirators were handed over, by the Bulgarians, to Leo III as requested.<ref name=":0" /> In 719, Anastasius was executed, along with other conspirators including Niketas Xylinitas and the archbishop of Thessalonica. Anastasius' wife Irene arranged for his burial in the Church of the Holy Apostles.<ref name=":3" />