|Emperor of the Byzantine Empire|
Constantine V and his father Leo III the Isaurian
|Died||14 September 775|
|Predecessor||Leo III the Isaurian|
|Successor||Leo IV the Khazar|
|Wives||Tzitzak ("Irene of Khazaria")
|Father||Leo III the Isaurian|
|with Constantine V as co-emperor, 720–751|
|with Leo IV as co-emperor, 751–775|
|Usurpation of Artabasdos||741–743|
|with Constantine VI as co-emperor, 776–780|
|under Irene as regent, 780–790, and with her as co-regent, 792–797|
|Irene as empress regnant||797–802|
Twenty Years' Anarchy
Early life 
Constantine was born in Constantinople, the son and successor of Emperor Leo III and Maria. In August 720 he was associated on the throne by his father, who had him marry Tzitzak, daughter of the Khazar khagan Bihar. His new bride was baptized as Irene (Eirēnē, "peace") in 732. Constantine V succeeded his father as sole emperor on 18 June 741.
Civil war against Artabasdos 
In June 741 or 742, while Constantine was crossing Asia Minor to campaign on the eastern frontier against the Umayyad Caliphate under Hisham ibn Abd al-Malik, he was attacked by the forces of his brother-in-law Artabasdos, husband of his older sister, Anna. Artabasdos was the stratēgos of the Armeniac theme.
Constantine was defeated and sought refuge in Amorion, while Artabasdos advanced on Constantinople and was accepted as Emperor. Constantine received the support of the Anatolic and Thracesian themes; Artabasdos secured the support of the themes of Thrace and Opsikion, in addition to his own Armeniac soldiers.
The rival emperors bided their time making military preparations. Artabasdos marched against Constantine in May 743 but was defeated. Three months later Constantine defeated Artabasdos' son Niketas and headed for Constantinople. In early November Constantine was admitted into the capital and immediately turned on his opponents, having them blinded or executed.
The usurpation of Artabasdos was connected with restoring the veneration of images, leading Constantine to became perhaps an even more fervent iconoclast than his father. Constantine's avowed enemies over this extremely emotional issue, the iconodules, applied to him the derogatory epithet Kopronymos ("dung-named", from kopros, meaning "feces" or "animal dung", and onoma, "name"). Using this obscene name, they spread the rumour that as an infant he had defecated in his baptismal font, or the imperial purple cloth with which he was swaddled.
Campaign pro iconoclasm 
Constantine's position on Iconoclasm was clear:
....He cannot be depicted. For what is depicted in one person, and he who circumscribes that person has plainly circumscribed the divine nature which is incapable of being circumscribed. 
In February 754 Constantine convened a synod at Hieria, which was attended entirely by Iconoclast bishops. The council approved of Constantine's religious policy and secured the election of a new Iconoclast patriarch, but refused to follow in all of Constantine's views. The council confirmed the status of Mary as Theotokos, or Mother of God, reinforced the use of the terms "saint" and "holy" as meet, and condemned the desecration, burning, or looting of churches in the quest to quench Iconophiles.
The synod was followed by a campaign to remove images from the walls of churches and to purge the court and bureaucracy of Iconodules. Since monasteries tended to be strongholds of Iconophile sentiment, Constantine specifically targeted the monks, pairing them off and forcing them to marry nuns in the Hippodrome and expropriating monastic property for the benefit of the state or the army. The repressions against the monks (culminating in 766) were largely led by the Emperor's general Michael Lachanodrakon, who threatened resistant monks with blinding and exile. An iconodule abbot, Stephen Neos, was brutally lynched by a mob at the behest of the authorities. As a result many monks fled to Southern Italy and Sicily.
By the end of Constantine's reign, Iconoclasm had gone as far as to brand relics and prayers to the saints as heretical. Ultimately, iconophiles considered his death a divine punishment. In the 9th century he was disinterred, and his remains were thrown into the sea.
Campaigns against the Arabs and Bulgaria 
Constantine was an able general and administrator. He reorganised the themes, the military districts of the Empire, and created new field army divisions called tagmata. This organization was intended to minimize the threat of conspiracies and to enhance the defensive capabilities of the Empire. With this reorganized army he embarked on campaigns on the three major frontiers.
In 746, profiting by the unstable conditions in the Umayyad Caliphate, which was falling apart under Marwan II, Constantine invaded Syria and captured Germanikeia (modern Maraş, his father's birthplace). He organised the resettlement of part of the local Christian population to Imperial territory in Thrace. In 747 his fleet destroyed the Arab fleet off Cyprus. In 752 he led an invasion into the new Abbasid Caliphate under As-Saffah. Constantine captured Theodosioupolis and Melitene (Malatya) and again resettled some of the population in the Balkans. These campaigns failed to secure any concrete gains (apart from additional population employed to strengthen another frontier), but it is important to note that under Constantine V the Empire had gone on the offensive.
The successes in the east made it possible to pursue an aggressive policy in the Balkans. With the resettlement of Christian populations from the East into Thrace, Constantine V aimed to enhance the prosperity and defence of the area, causing concern to the Empire's northern neighbour, Bulgaria, and leading the two states to clash in 755. Kormisosh of Bulgaria raided as far as the Anastasian Wall but was defeated in battle by Constantine V, who inaugurated a long series of nine successful campaigns against the Bulgarians in the next year, scoring a victory over Kormisosh's successor Vinekh at Marcelae.
Three years later, Constantine was defeated in the battle of the Rishki Pass, but the Bulgarians did not exploit their success. In 763, he sailed to Anchialus with 800 ships carrying 9,600 cavalry and some infantry. Constantine's victories, including that at Anchialus in 763, caused considerable instability in Bulgaria, where six monarchs lost their crowns on account of their failures.
In 775, Constantine was persuaded to reveal to the Bulgarian ruler Telerig the identities of his agents in Bulgaria, and they were promptly eliminated. Constantine thus began preparations for a new campaign against the Bulgarians, during which he died, on September 14, 775.
Constantine's campaigns were costly; during his reign the Byzantine Empire's annual revenues were reduced to about 1,800,000 nomismata due to his various wars and the Arab conquests.
By his first wife, Tzitzak ("Irene of Khazaria"), Constantine V had one son:
- Leo IV, who succeeded as emperor.
By his second wife, Maria, Constantine V is not known to have had children.
By his third wife, Eudokia, Constantine V had five sons and a daughter, including:
- Christopher, Caesar
- Nikephoros, Caesar
- Niketas, Nobelissimos
- Eudokimos, Nobelissimos
- Anthimos, Nobelissimos
- Nikephoros, Antiherreticus I, PG 100, 301C; trans. Bryer & Herrin
- The Oxford Dictionary of Byzantium, Oxford University Press, 1991.
Media related to Constantine V at Wikimedia Commons
Constantine VBorn: 718 Died: 14 September 775