In the 7th century Byzantium experienced the first Arab threat. When the Armenian governor Theodore Rshtuni submitted to Arabs, Constant II, the emperor of Constantinople, organized a campaign against Armenia. However, the Arabs conquered Armenia, and started to collaborate with the opposition of the emperor in Constantinople. His brother Theodosius organized a plot, using the money, received from the Arabs. Constant II executed him to solve the problem...
Then the emperor, leaving his family, went to Thessaloniki, then lived in Athens, and later moved to Taranto. When he came to Rome, he was solemnly met by the Pope, and then went to Syracuse, where he wanted to found his new capital. As a result of a plot, the emperor was killed. The rebellion was stifled by the armies, that remained faithful to Constantine IV, the young heir of Constant II.
The external threat intensified during his rule (668–685). Arabs, who yearly raided Asia Minor, approached Constantinople. The Arab Moavia, who united a caliphate under his power, was preparing Naval forces to attack the empire. Constantinople had been beleaguered by the Arab fleet for some years. In the end, the Arabs retreated with big losses. The wildfire – oil, burnt in barrels and thrown to enemy ships – was very significant for the victory. Byzantium signed a favorable peace treaty with the caliphate for 30 years. Constantine IV reestablished good relations with Rome, calling the sixth Ecumenical Council. It seemed that everything was fine, but the emperor died and Justinian II inherited him. His reign is considered one of the most tragic and merciless reigns in Byzantium. He managed to sign a favorable peace treaty with the Arabs, take back Armenia and other Caucasian countries, using the disorder in the caliphate.
The emperor used to erect expensive buildings, and it made easier the organization of a plot against him. Justinian II was overthrown, maimed (his nickname Rhinotmetos means 'with cut nose'), and exiled to Hersones (today's Ukraine). He escaped to Khazars (marrying the sister of their king), and then to the Bulgarian khan. Using the help of the latter, Justinian took Constantinople, and revenged his enemies (the patriarch was blinded, etc.). Justinian II considered his return to power a divine disposal, and tried to emphasize his piety. When Pope Constantine I came, he organized a splendid reception. Strafe expeditions, dragooned by the emperor to Ravenna (Italy) and Hersones, led to rebellions in these cities. A Vardan, supported by the Khazars, became the emperor in Hersones. The army of Justinian joined him as well, and the emperor was overthrown and executed. The Heraclian dynasty, who ruled Byzantium for a century, ended with him.
