Lion was a Téméraire class 74-gun third rate ship of the line of the French Navy, which later served in the Royal Navy. She was named Lion on 23 April 1790 and built at Rochefort from August 1791 until June 1794. She was renamed Marat on 28 September 1793 and then Formidable on 25 May 1795, with the changing fortunes of the French Revolution.

The action of 6 November 1794 was a naval engagement during the French Revolutionary Wars. Two British ships of the line, HMS Alexander and HMS Canada were intercepted while returning to Britain through the Celtic Sea by a large French squadron. The French squadron had sailed from Brest in search of an inward bound British convoy in October, but instead encountered the two British ships returning from escorting an outward-bound convoy. There had been no warning of the French approach as the British force assigned to watch Brest was absent at Plymouth due to the policy of operating a distant blockade.