Nossa Senhora da Conceição was a 90-gun first-rate ship of the line of the Portuguese Navy which was launched at Lisbon on 13 July 1771.

She was refitted and renamed Príncipe Real in 1794, and from 1798 to 1800 served in the Mediterranean Sea as the flagship of a Portuguese squadron which saw service alongside British Admiral Horatio Nelson.

In mid-September 1798, a squadron of Portuguese ships arrived at French-occupied Malta to assist a British siege.

[2] HMS Foudroyant departed Naples on 6 August 1799, in company with the frigate Syren, and Príncipe Real.

On 18 October 1800, an Anglo-Portuguese squadron shared in the capture of the Ragusan polacca Madonna Della Gratia e San Gaetano, which was carrying plate, amongst other cargo.