I realize the emperors ultimately reversed their position on that matter, but also that the Great Schisms official declaration only formally recognized the growing divide of preceding centuries. Iconoclasm was far from the sole or leading element in that, but did real, significant and permanent damage to the relationship between the Greek and Roman churches. When ones political and religious leaders go around calling people idolaters for half a century, that cannot be dismissively shrugged off once new leaders decide it is not idolatry after all.