The Battle of Comacchio in 809 was a naval battle between a Byzantine fleet dispatched from Venice and the Frankish garrison of the island of Comacchio. A Byzantine fleet from Constantinople under its commander Paul, the governor of Cephalonia, arrived in Venice by way of Dalmatia and sent a fleet detachment to anchor at Comacchio. They skirmished with the Franks, were defeated and retreated to Venice.
Fetching the article from Wikipedia…
Text from the Wikipedia article “Battle of Comacchio”, available under CC BY-SA 4.0.