The Battle of Ravenna was fought between the troops of Byzantine Emperor Leo III, and a force of Italians raised by Pope Gregory II in defense of image worship, which Emperor Leo had outlawed. After a prolonged struggle, the Greeks were overcome.
Editors. "Battle of Ravenna". The Literary Encyclopedia. First published 01 May 2009
[http://www.litencyc.com/php/stopics.php?rec=true&UID=6824, accessed 23 May 2015.]