The Biscay campaign of June 1795 consisted of a series of manoeuvres and two battles fought between the British Channel Fleet and the French Atlantic Fleet off the Southern coast of Brittany in the Bay of Biscay during the French Revolutionary Wars. In late May 1795, a British battle squadron of six ships of the line under Vice-Admiral William Cornwallis was sent by Admiral Lord Bridport to enforce the blockade of the French port of Brest, the home port of the French Atlantic Fleet. On 8 June, Cornwallis discovered a convoy of merchant vessels travelling from Bordeaux to Brest under the protection of a small squadron under Contre-amiral Jean Gaspard Vence. Cornwallis attacked the convoy, Vence retreating under the protection of batteries on the fortified island of Belle Île as Cornwallis seized eight ships from the convoy. As Cornwallis sent his prizes back to Britain the main French fleet at Brest under Vice-amiral Villaret de Joyeuse put to sea to protect Vence's remaining ships.
On 16 June, Cornwallis's squadron encountered Villaret's fleet, in conjunction with Vence's force, off Penmarck Point. Cornwallis had misunderstood the signals from Captain Robert Stopford on the scouting frigate HMS Phaeton and had sailed much too close to the larger French fleet. When he realised his error, the British admiral turned his squadron westwards, retreating away from the French coast with Villaret's force in pursuit. Light winds and poorly loaded ships delayed his escape, and on 17 June the French vanguard caught up with his rearguard. Throughout the day the French and British ships exchanged fire and by the late afternoon the rearmost British ship HMS Mars was in danger of being overwhelmed. Cornwallis responded by interposing his 100-gun flagship HMS Royal Sovereign between the British and French forces. The heavy broadsides of the flagship drove back the French and soon afterwards Villaret recalled his ships, concerned by sails on the horizon which he may have believed to be the rest of the Channel Fleet, although in reality they were a British merchant convoy. The battle is known in British histories as Cornwallis's Retreat.