The advantages they derived from this alliance were so great, that they resisted the promises and the threats of Mithridates, when he engaged in hostilities with the Romans.  This monarch, therefore, resolved to employ his whole force by sea and land against them:  they were not however dismayed, but placed a firm reliance on their skill in maritime affairs.  They divided their fleet into three squadrons:  one drawn up in a line protected the entrance of the harbour; and the other two, at a greater distance from the shore, were stationed to watch the approach of the enemy.  Mithridates also divided his fleet, which was more numerous than that of the Rhodians, into three squadrons; one of these he himself commanded, on board of a quinquereme, and directed to attack the squadron which was protecting the port.  The Rhodians gradually retired before the enemy, till they came close to the mouth of the harbour:  Mithridates in vain endeavoured to break their line, and force an entrance; in all his attempts he was defeated with considerable loss; and his land forces, which he had embarked in transports, being dispersed in a storm, he was obliged to retire from before the city.

The Romans acknowledged the benefits they derived from the valour of the Rhodians on this occasion; and they again experienced it, in the war which Pompey carried on against the Cilician pirates, though that commander took all the merit to himself.  In the civil war between him and Caesar, they assisted the former with a numerous fleet, under the command of one of their best seamen, who distinguished himself above all Pompey’s captains, and gained very considerable advantages over Caesar’s fleet.  On the death of Pompey they joined Csesar:  this exposed them to the hostility of Cassius; they endeavoured to pacify him by promising to recal the ships they had sent to the assistance of Caesar, but he demanded the delivery of their whole fleet, and that he should be put in possession of their harbour and city.  To these terms they would not accede, but prepared for war, by equipping a fleet of thirty-three ships, and placing it under the command of one of their best officers.  A battle ensued which was fought on both sides with great skill and bravery; but the Rhodians were obliged to yield to the superior number of the Roman fleet, and to return to the harbour, having lost two of their ships, and the rest being very much damaged.  It is remarked by the ancient historians who relate this battle, that it was the first time the Rhodians were fairly overcome in a sea-fight.

Cassius followed up his success by bringing against Rhodes a fleet of eighty ships of war, and 200 transports.  Against this formidable armament the Rhodians again put to sea, and a second battle ensued, which was more obstinately contested than the first:  the Romans however were again victorious, and the city of Rhodes was blocked up by sea and land.  Its fate was soon determined; for some of the inhabitants, dreading a famine, opened the gates to the Romans.  Cassius, besides other severe terms, obliged the Rhodians to deliver up all their ships, and all their public treasures; the temples were plundered, and 8000 talents extorted from private individuals, besides a fine of 500 levied on the city.