Although Antony was an Iconodule, he became an Iconoclast in 815, when Emperor Leo V the Armenian reinstituted Iconoclasm. The reason for Antony's change of heart is said to have included his hope for attaining the patriarchate.
Initially, Antony held a pro-icon stance; however, his allegiance shifted to iconoclasm in 815 when Emperor Leo V the Armenian revived this movement. His motivation for this change may have been linked to his desire for greater influence and authority within the church, such as the position of patriarch.