Now this exaction by the Byzantines of a duty upon goods brought from the Pontus, being a heavy loss and burden to everybody, was universally regarded as a grievance; and accordingly an appeal from all those engaged in the trade was made to the Rhodians, as acknowledged masters of the sea: and it was from this circumstance that the war originated of which I am about to speak. For the Rhodians, roused to action by the loss incurred by themselves, as well as that of their neighbours, at first joined their allies in an embassy to Byzantium, and demanded the abolition of the impost. The Byzantines refused compliance, being persuaded that they were in the right by the arguments advanced by their chief magistrates, Hecatorus and Olympidorus, in their interview with the ambassadors. The Rhodian envoys accordingly departed without effecting their object. But upon their return home, war was at once voted against Byzantium on these grounds; and messengers were immediately despatched to Prusias inviting his co-operation in the war: for they knew that Prusias was from various causes incensed with the Byzantines.