Nossa Senhora da Conceição was launched at Lisbon on 13 July 1771 for the Portuguese Navy as a first rate ship of the line of 90 guns. In 1793 she was the flagship of the squadron that the Portuguese Navy provided to assist the British Royal Navy's Channel Fleet. The next year the Portuguese government refitted her and changed her name to Príncipe Real. In 1798-1800 Príncipe Real served in the Mediterranean as the flagship of the Portuguese squadron assisting Admiral Nelson.