The Battle of Ravenna in 729 was fought between the troops of the Eastern Roman (Byzantine) Exarchate of Ravenna and a force of Italians. This was in response to Emperor Leo III the Isaurian outlawing the veneration of holy icons, which Pope Gregory II was against. After a fierce battle, the Eastern Roman Army was overcome and thousands of Byzantines were killed.
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Battle of Ravenna (729) Wikipedia(Text) CC BY-SA