Historical Context
Joannicius lived during the Byzantine iconoclast controversy, a period of imperial opposition to the veneration of icons that spanned much of the 8th and early 9th centuries. By tradition he was born into a family with iconoclast leanings and, during his army service, initially embraced iconoclasm himself.
According to tradition he repented after an encounter with a clairvoyant monk on Mount Olympus who confronted him over his rejection of icon veneration. Thereafter he became a defender of icons, and tradition credits him with prophesying the restoration of icon veneration to the Byzantine Church — a restoration his devotees associate with that effected under the Empress Theodora.
Mysian Olympus, where he lived, was a major center of Eastern Christian monasticism from the 8th century onward, its hermitages and monasteries closely tied to monastic resistance against iconoclast policy.