HMS Emerald (1795) dispatched a squadron of five ships, including "Emerald" and commanded by Nelson in the 74-gun , to locate a large invasion fleet that had left Toulon. After receiving intelligence on 22 May, Nelson correctly predicted the French fleet's destination and set course for Alexandria where the British captured or destroyed all but two of the French ships at the Battle of the Nile, which occurred between 1–3 August 1798. "Emerald" missed the battle; having previously become separated from the rest of the squadron in a storm on 21 May, she arrived at Aboukir Bay on 12 August. When Nelson left
Atlantic campaign of 1806 sailed from Cadiz and was intercepted by Nelson, resulting in the Battle of Trafalgar. Although Nelson was killed at the height of the battle, his squadron inflicted a devastating defeat on the combined fleet, capturing or destroying 17 French or Spanish ships, including Villeneuve's flagship. The battered remnants of the French Mediterranean and Spanish Atlantic fleets retreated to Cadiz, although four French ships fled north and were intercepted and captured at the Battle of Cape Ortegal two weeks later. In total, the campaign cost Napoleon 13 French and 12 Spanish ships, eliminating any possibility of even regional superiority at sea