In anticipation of the start of Britain's involvement in the French Revolutionary War after the execution of King Louis XVI, "Agamemnon" was recommissioned on 31 January 1793. She was placed under the command of Captain Horatio Nelson, and after provisioning joined the fleet lying at anchor at the Nore. She subsequently sailed to join the Mediterranean fleet under Vice-Admiral Hood, which was blockading the French port of Toulon. On 27 August the town of Toulon declared its allegiance to the Royalist Bourbon cause, and Hood's fleet moved in to take control of the naval dockyard and the 30 French ships of the line that were in the harbour. After capturing 19 of the ships, "Agamemnon" was sent to Naples to ask King Ferdinand IV for reinforcements with which to secure the town; he agreed to provide 4,000 men. When the revolutionary army, commanded by Napoleon Buonaparte, launched its assault against Toulon, the troops proved insufficient to hold it, and they were forced to abandon the town. Later in the autumn, "Agamemnon" fought the inconclusive Action of 22 October 1793 against a French frigate squadron off Sardinia.