Photian schism in the context of "Patriarch of Constantinople"

Pope John VIII (Latin: Ioannes VIII; died 16 December 882) was the bishop of Rome and ruler of the Papal States from 14 December 872 to his death. He is often considered one of the most able popes of the 9th century.

John devoted much of his papacy to attempting to halt and reverse the Muslim gains in southern Italy and their march northwards. When his efforts to obtain assistance from either the Franks or the Byzantines failed, John strengthened the defences of Rome. He supported Methodius of Thessalonica in his mission to the Slavs, defended him against the Carolingian rulers and Bavarian clergy, and authorized the translation of the Bible into Old Church Slavonic. John also extended diplomatic recognition to the Duchy of Croatia and resolved the Photian schism. John's pontificate ended with his assassination, and the papacy became significantly weaker in the aftermath.

Photios I of Constantinople (Greek: Φώτιος, Phōtios; c. 815—6 February 893), also spelled Photius (/ˈfoʊʃəs/), was the Ecumenical Patriarch of Constantinople from 858 to 867 and from 877 to 886. He is recognized in the Eastern Orthodox Church as 'Saint Photius the Great'.

Photios I is widely regarded as the most powerful and influential church leader of Constantinople subsequent to John Chrysostom's archbishopric around the turn of the fifth century. He is also viewed as the most important intellectual of his time—"the leading light of the ninth-century renaissance". He was a central figure in both the conversion of the Slavs to Christianity and the Photian schism, and is considered "[t]he great systematic compiler of the Eastern Church, who occupies a similar position to that of Gratian in the West," and whose "collection in two parts... formed and still forms the classic source of ancient Church Law for the Greek Church".