Riou remained many months at the Cape trying to patch up the _Guardian_, and repair it so as to bring it back to port; but all his exertions were fruitless, and in October the Admiralty despatched the _Sphinx_ ship-of-war to bring him and the survivors of his crew to England, where they landed shortly after. There was, of course, the usual court-martial held upon him for the loss of his ship, but it was merely a matter of form. At its conclusion he was complimented by the Court in the warmest terms; and "as a mark of the high consideration in which the magnanimity of his conduct was held, in remaining by his ship from an exalted sense of duty when all reasonable prospects of saving her were at an end," he received the special thanks of the Admiralty, was made commander, and at the same time promoted to the rank of post captain. No record exists of the services of Captain Riou from the date of his promotion until 1794, when we find him in command of his Majesty's ship _Rose_, assisting in the reduction of Martinique. He was then transferred to the _Beaulieu_, and remained cruising in the West Indian seas till his health became so injured by the climate that he found himself compelled to solicit his recall, and he consequently returned to England in the _Theseus_ in the following year. Shortly after, in recognition of his distinguished services, he was appointed to the command of the royal yacht, the _Princess Augusta_, in which he remained until the spring of 1790. So soon as his health was sufficiently re-established, he earnestly solicited active employment, and he was accordingly appointed to the command of the fine frigate, the _Amazon_, thirty-eight guns, whose name afterwards figured so prominently in Nelson's famous battle before Copenhagen. After cruising about in her on various stations, and picking up a few prizes, the _Amazon_, early in 1801, was attached to Sir Hyde Parker's fleet, destined for the Baltic. The last letter which Riou wrote home to his mother was dated Sunday, the 29th March, "at the entrance to the Sound;" and in it he said:--"It yet remains in doubt whether we are to fight the Danes, or whether they will be our friends." Already, however, Nelson was arranging his plan of attack, and on the following day, the 30th, the Admiral and all the artillery officers were on board the _Amazon_, which proceeded to examine the northern channel outside Copenhagen Harbour. It was on this occasion that Riou first became known to Nelson, who was struck with admiration at the superior discipline and seamanship which were observable on board the frigate during the proceedings of that day.