The Melkites played a leading role in condemning the iconoclast controversy when it re-appeared in the early 9th century, and were among the first of the Eastern churches to respond to the introduction of the filioque clause in the West.

The author of multiple treatises, ranging in subject matter from the iconoclast controversy to Spanish Adoptionism to critiques of the Carolingian royal family, Agobard is best known for his critiques of Jewish religious practices and political power in the Frankish realm.

In theology and church history, he has published his views on the ordination of women, the infallibility of the church, the iconoclast controversy, and the work of Gregory Palamas.

He then deposed the iconoclast Patriarch John VII Grammatikos and secured the appointment of Methodios as his successor, bringing about the end of the iconoclast controversy.

It houses also an 8th-century Byzantine statue portraying the Madonna, probably brought here during the iconoclast controversy.

The iconoclast controversy returned in the early 9th century, only to be resolved once more in 843 during the regency of Empress Theodora, who restored the icons.

He had once opposed the veneration of icons but urged the calling of an ecumenical council to address the iconoclast controversy.