When general inconvenience and loss of profit was caused by the Byzantines levying duties on exports from the <a class="linkToPlace" target="_blank" href="/place?placename=Pontus&groupId=910&placeId=1634">Pontus</a>, all the traders were aggrieved and brought their complaint before the Rhodians who were considered the supreme authority in maritime matters.
This was the origin of the war the history of which I am about to tell.
For the Rhodians, roused to action by the loss they suffered themselves and the detriment to neighbouring states, at first together with their allies sent an embassy to <a class="linkToPlace" target="_blank" href="/place?placename=Byzantium&groupId=415&placeId=767">Byzantium</a> demanding the abolition of the duty.
The Byzantines were not disposed to make any concession, being convinced of the justice of their cause by the terms in which Hecatodorus and Olympiodorus, their chief magistrates at the time, replied to the Rhodian envoys. The Rhodians therefore took their departure without having accomplished anything, and on their return war was declared by <a class="linkToPlace" target="_blank" href="/place?placename=Rhodes&groupId=931&placeId=1665">Rhodes</a> on <a class="linkToPlace" target="_blank" href="/place?placename=Byzantium&groupId=415&placeId=767">Byzantium</a> for the reasons above stated.
They at once sent envoys to Prusias pressing him to take part in the war, for they knew that for various reasons he was offended with the Byzantines.
Walbank Commentary