Editing Constantine V (section)

=== Repeated campaigns against the Bulgarians ===
[[File:Byzantine–Bulgarian Wars (741-775).png|upright=0.8|thumb|Byzantine and Bulgarian campaigns during the reign of Constantine (741–775)]]
The successes in the east made it possible to then pursue an aggressive policy in the Balkans. Constantine aimed to enhance the prosperity and defence of Thrace by the resettlement there of Christian populations transplanted from the east. This influx of settlers, allied to an active re-fortification of the border, caused concern to the Empire's northern neighbour, [[Bulgaria]], leading the two states to clash in 755. [[Kormisosh]] of Bulgaria raided as far as the [[Anastasian Wall]] (the outermost defence of the approaches to Constantinople) but was defeated in battle by Constantine, who inaugurated a series of nine successful campaigns against the Bulgarians in the next year, scoring a victory over Kormisosh's successor [[Vinekh]] at [[battle of Marcellae (756)|Marcellae]]. In 759, Constantine was defeated in the [[Battle of the Rishki Pass]], but the Bulgarians were not able to exploit their success.<ref>Bury, p. 11</ref><ref>Jenkins, pp. 71–72</ref>

Constantine campaigned against the Slav tribes of Thrace and Macedonia in 762, deporting some tribes to the Opsician theme in Anatolia, though some voluntarily requested relocation away from the troubled Bulgarian border region. A contemporary Byzantine source reported that 208,000 Slavs emigrated from Bulgarian controlled areas into Byzantine territory and were settled in Anatolia.<ref>Bury, p. 10</ref><ref>Ostrogorsky, p. 168</ref><ref>Fine, pp. 76–77</ref>

A year later he sailed to [[Pomorie|Anchialus]] with 800 ships carrying 9,600 cavalry and some infantry, gaining a [[Battle of Anchialus (763)|victory]] over Khan [[Telets of Bulgaria|Telets]]. Many Bulgar nobles were captured in the battle, and were later slaughtered outside the [[Golden Gate (Constantinople)|Golden Gate]] of Constantinople by the circus factions. Telets was assassinated in the aftermath of his defeat. In 765 the Byzantines again successfully invaded Bulgaria, during this campaign both Constantine's candidate for the Bulgarian throne, [[Toktu of Bulgaria|Toktu]], and his opponent, [[Pagan of Bulgaria|Pagan]], were killed. Pagan was killed by his own slaves when he sought to evade his Bulgarian enemies by fleeing to [[Varna, Bulgaria|Varna]], where he wished to defect to the Emperor. The cumulative effect of Constantine's repeated offensive campaigns and numerous victories caused considerable instability in Bulgaria, where six monarchs lost their crowns due to their failures in war against Byzantium.<ref>Bury, p. 11</ref><ref>Treadgold (1997), p. 363</ref><ref>Curta, pp. 85–88</ref>

In 775, the Bulgarian ruler [[Telerig of Bulgaria|Telerig]] contacted Constantine to ask for sanctuary, saying that he feared that he would have to flee Bulgaria. Telerig enquired as to whom he could trust within Bulgaria, and Constantine foolishly revealed the identities of his agents in the country. The named Byzantine agents were then promptly eliminated.<ref>Fine, p. 77</ref> In response, Constantine set out on a new campaign against the Bulgarians, during which he developed [[carbuncle]]s on his legs. He died during his return journey to Constantinople, on 14 September 775. Though Constantine was unable to destroy the Bulgar state, or impose a lasting peace, he restored imperial prestige in the Balkans.<ref>Bury, p. 11</ref><ref>Ostrogorsky, p. 169</ref><ref>Curta, p. 88</ref>