Constantine V (; ; July 718 – 14 September 775), was Byzantine emperor from 741 to 775. His reign saw a consolidation of Byzantine security from external threats. As an able military leader, Constantine took advantage of civil war in the Muslim world to make limited offensives on the Arab frontier. With this eastern frontier secure, he undertook repeated campaigns against the Bulgars in the Balkans. His military activity, and policy of settling Christian populations from the Arab frontier in Thrace, made Byzantium's hold on its Balkan territories more secure. Religious strife and controversy was a prominent feature of his reign. His fervent support of Iconoclasm and opposition to monasticism led to his vilification by later Byzantine historians and writers, who denigrated him with the nicknames "the Dung-Named" (; ), because he allegedly defaecated during his baptism, and "the Equestrian" (; ), referencing the excrement of horses. However, the Byzantine Empire enjoyed a period of increasing internal prosperity during Constantine's reign. He was also responsible for important military and administrative innovations and reforms. Early life Constantine was born in Constantinople, the son and successor of Emperor Leo III and his wife Maria. In the Easter of 720, at two years of age, he was associated with his father on the throne, and crowned co-emperor by Patriarch Germanus I. In Byzantine political theory more than one emperor could share the throne; however, although all were accorded the same ceremonial status, only one emperor wielded ultimate power. As the position of emperor was in theory, and sometimes in practise, elective rather than strictly hereditary, a ruling emperor would often associate a son or other chosen successor with himself as a co-emperor to ensure the eventual succession. To celebrate the coronation of his son, Leo III introduced a new silver coin, the miliaresion; worth a 12th of a gold nomisma, it soon became an integral part of the Byzantine economy. In 726, Constantine's father issued the Ecloga; a revised legal code, it was attributed to both father and son jointly. Constantine married Tzitzak, daughter of the Khazars's khagan Bihar, an important Byzantine ally. His new bride was baptized Irene (Eirēnē, "peace") in 732. On his father's death, Constantine succeeded as sole emperor on 18 June 741. Historical accounts of Constantine make reference to a chronic medical condition, possibly epilepsy or leprosy; early in his reign this may have been employed by those rebelling