Catherine the Great promotes Lambros Katsonis to Lieutenant Colonel on July 24, 1789.

Katsonis is an aggressive commander, and does not hesitate to confront the Ottoman navy whenever possible; in June he had defeated a Turkish fleet of fourteen vessels between Syros and Mykonos, and in the next month he scored another victory in a battle between Syros and Delos.

As a Greek privateer, Katsonis had participated in the Orlov Revolt of 1770, then entered the service of the Russian Empire under Catherine, reaching the rank of Major.

Following the outbreak of the Russo–Turkish War in 1787, he had gone to Trieste in spring 1789 and recruited Greek crews and ships, forming a fleet to operate Ottoman shipping in the Ionian and Aegean Seas.

On his arrival in the Aegean in summer 1789, Katsonis had seized, garrisoned, and fortified the island of Kea as a base, leading from there numerous raids against Ottoman shipping in the northern Aegean, from the Chalcidice to the Dardanelles, and had even engaged in a short but eventful blockade of the Dardanelles Straits.

Katsonis occasionally collaborates with another Russian flotilla of five state-funded and four Greek privateer vessels under the Maltese captain Guglielmo Lorenzo that also operates in the Aegean, but the latter's attempt to subordinate Katsonis to his command is strongly rejected by Katsonis, who insists on the independence of his command, and the opportunity for uniting the two fleets to greater effect is lost.

Indeed, relations sour to such extent that Katsonis prohibits the islanders from assisting Lorenzo's flotilla, while many of the latter's crewmen defect to Katsonis, lured by the greater salary he gives his men.

Katsonis' fleet is far more effective and experienced than that of Lorenzo, and Katsonis himself, as a Greek, has far broader appeal among the Greek populations of the Aegean, who regard him as a hero.

Lorenzo, on the other hand, despite assembling a large fleet of thirty-six vessels, leaves the Aegean in August and returns to Sicily, declining to continue operations against the Ottomans as too risky.

Katsonis continues his successful activity, defeating a joint Turkish and Algerian fleet off Eleni (Makronisos) on = August 4, so that the Ottoman Porte attempts to bribe him by offering, through the dragoman of the fleet, Alexandros Mavrogenis, a full pardon, the right to settle with his followers on whichever island he chooses, hereditary rule over it, and two hundred thoi=usand gold coins.

Katsonis with his fleet had left the Aegean in September 1789 for the Venetian-ruled Ionian Islands, to repair and replenish his ships.

In late August, however, the Ottoman fleet had arrived at Kea and sacked the island.

The men left behind had been killed, and the installations erected razed to the ground.

In early spring 1790, after having undertaken repairs to his ships, Katsonis with a fleet of nine vessels had returned to the Aegean.

Klephts (Greek for "thieves" and perhaps originally meaning just "brigands") are highwaymen turned self-appointed armatoloi, anti-Ottoman insurgents, and warlike mountain-folk who live in the Greek countryside.

Descendants of Greeks who had retreated into the mountains during the fifteenth century in order to avoid Ottoman rule, they carried on a continuous war against Ottoman rule and remain active as brigands.

Katsonis, having taken on board the klepht Androutsos and his eight hundred men, has raided Turkish shipping in the Aegean, advancing up to Tenedos in hopes of confronting an Ottoman fleet.

On April 15, they arrive at Kea, which they refortify and regarrison.

Katsonis had received news at Kea that an Ottoman squadron of nineteen vessels, including frigates and ships of the line, had exited the Dardanelles with explicit orders from the new Sultan, Selim III, to hunt him down and destroy him.

Katsonis had sailed forth to meet it, but adverse winds have delayed his progress, and on May 17 his fleet encounters the Ottoman squadron in the straits between Cape Kafireas of Euboea and the island of Andros.

The two fleets begin their engagement near noon, and the battle rages the entire day.

The fight is initially in favor of the Greeks, but at night the wind falls, and Katsonis' ships are unable to disengage.

An Algerian squadron of eleven to thirteen ships comes to the Ottomans' aid early in the morning of the next day.

The Greek flotilla is now in a critical position, attacked from two sides by over thirty ships of the line.

As the Greeks begin running low on ammunition, they reduce their rate of fire.

Katsonis' ships are now exposed to withering fire, their superstructures riddled with holes and with many officers dead, and their opponents move  to board their ships and take them by assault.

The Algerians manage to capture three ships, which later sink due to excessive damage.

In the end, Katsonis is forced to put his own heavily damaged flagship, Athena of the North, to the torch, and barely manages to escape with a few close comrades on a skiff between the Ottoman ships.

The battle ends with Katsonis' fleet having lost five hundred and sixty-five dead and fifty-three wounded and captured, while Katsonis with his remaining two vessels withdraws to Kythira.

The Ottoman and Algerian losses are also heavy, reportedly some three thousand men killed and many wounded.

Many vessels have to be towed home, and according to some reports a few sink on the way.

Nevertheless, Katsonis' fleet has been destroyed as an effective force.

The Ottomans also retake Kea, razing Katsonis' base here.