His Majesty's frigate Amethyst was one of the three "Penelope" class of Fifth Rates designed by Sir John Henslow in 1797 and ordered the same year. Built in Deptford Dockyard, she was launched on 23rd April 1799 and, with a full crew of 274 officers and men, entered service as soon as she was ready for sea. Measured at 1,042 tons, she was 150 feet in length with a 39½ beam and carried a main armament of 26-18pdrs. on her upper deck, with 10 additional cannon and 8-32pdr. carronades mounted elsewhere. Her career was a relatively short one, barely twelve years in fact, until she was wrecked in 1811, but during it she saw action many times and made her reputation by capturing two French frigates, each larger than herself, within the space of five months.
On 10th November 1808, Amethyst, under the command of Captain Michael Seymour, was patrolling off the Île de Groix when she sighted the 40-gun French frigate Thétis which had just left L'Orient bound for Martinique with troops and stores. Amethyst gave chase immediately and was within range by 9.30pm. at which time a furious action began. By 10.00 pm. both ships had lost their mizzenmasts and at 11.00pm., just as Thétis was preparing to board Amethyst, the latter swept her fo'c'sle with a tremendous broadside causing heavy casualties. At 12.30am. Thétis had had enough, struck her colours and surrendered; out of a crew of 436, she had lost 134 killed and 102 wounded and, although damaged, the vessel herself was purchased into the Royal Navy, repaired and recommissioned with the new name of Brune.
Five months later, on the morning of 5th April 1809, Amethyst was skirting the northern coast of Spain, near the Cordouon lighthouse, when she sighted the 40-gun French frigate Niémen. After a long chase lasting twelve hours, the two ships were finally in range at 11.30pm., whereupon Amethyst opened fire with her bow-chasers. A prolonged running battle then ensued which was fought with great determination on both sides; only when each vessel was practically dismasted did Niémen cease firing and, when the British frigate Arethusa appeared on the scene unexpectedly at about 3.45am. on the 6th, Niémen lowered her lights as a signal of submission and surrendered. Being only nine months old, she made a valuable addition to the British fleet and Captain Seymour was rewarded with a well-deserved baronetcy for his skill and tenacity against heavy odds on two separate occasions. Both these actions were painted by Thomas Whitcombe, engraved by T. Sutherland and published in Ralfe's Naval Chronology, thus providing the artist with his inspiration.