text: Late in his reign, this man repulsed an Arab raid in the Battle of Akroinon.
full_question: Late in his reign, this man repulsed an Arab raid in the Battle of Akroinon. This ruler married his daughter Anna to his ally Artabasdos, who nevertheless tried to seize the throne upon this man’s death. He came to power when he repulsed the Second Arab Siege of Constantinople, thus ending the Twenty Years’ Anarchy. The Patriarch of Constantinople Germanus I resigned rather than enforce this man’s decree that forbade the veneration of images. The First Iconoclasm was instituted by, for 10 points, what Byzantine emperor who founded the Isaurian Dynasty?
first_sentence: Late in his reign, this man repulsed an Arab raid in the Battle of Akroinon.