USS Constitution, also known as Old Ironsides, is a wooden-hulled, three-masted heavy frigate of the United States Navy named by President George Washington after the United States Constitution. She is the world's oldest commissioned naval vessel still afloat. [Note 1] She was launched in 1797, one of six original frigates authorized for construction by the Naval Act of 1794 and the third constructed. Joshua Humphreys designed the frigates to be the young Navy's capital ships, and so Constitution and her sisters were larger and more heavily armed and built than standard frigates of the period. She was built at Edmund Hartt's shipyard in the North End of Boston, Massachusetts. Her first duties were to provide protection for American merchant shipping during the Quasi-War with France and to defeat the Barbary pirates in the First Barbary War.