USS Syren (later Siren) was a brig of the United States Navy built at Philadelphia in 1803. She served during the First Barbary War and the War of 1812 until the Royal Navy captured her in 1814. The British never commissioned her but apparently used her for a year or so as a lazaretto, or a prison vessel. She then disappears from records. Description Syren was designed by Benjamin Hutton, Jr. of Philadelphia and built for the Navy in 1803 at Philadelphia by shipwright Nathaniel Hutton and launched on 6 August 1803. She was commissioned in September and Lieutenant Charles Stewart was appointed in command. She was sharper, but smaller than USS Argus (1803), yet carried the same armament. Both vessels were built the same year for the First Barbary War. Service history in US Navy First Barbary War Syren departed Philadelphia on 27 August 1803 and reached Gibraltar on 1 October. A fortnight later she sailed via Livorno to Algiers carrying presents and money to the Dey of Algiers. She then sailed to Syracuse, Sicily, where she arrived early in January 1804. The first action Syren was involved in was an attack aimed at destroying , a frigate that had run aground the previous autumn and that Tripolitan gunboats had then captured. To prevent Philadelphia from opposing his planned operations against Tripoli, the commander of the American squadron in the Mediterranean, Commodore Edward Preble, decided to destroy her. To achieve this, Syren and ketch sailed from Syracuse on 3 February 1804 and proceeded to Tripoli, which they reached on 7 February. However, before the American ships could launch their attack, they were driven off by a violent gale and did not get back off Tripoli until 16 February. Before the attack Syren tied up alongside Intrepid to transfer some of her crew for the assault on Philadelphia. Aboard Intrepid, under the command of Stephen Decatur, sailors from both Intrepid and Syren succeeded in burning Philadelphia. Also present during the assault was Thomas Macdonough of Syren. Syren returned to Syracuse on the morning of 19 February. On 9 March, she and sailed for Tripoli. Soon after their arrival, on 21 March 1804, she captured the armed brig Transfer belonging to the Pasha. Stewart took Transfer into US service and renamed her . She then served in the American squadron. The very next day Syren captured a polacca named Madona Catapolcana