The Barbary Wars were two wars fought at different times over the same reasons between the United States and the Barbary states (the de jure Ottoman Empire possessions of, but de facto independent, Tunis, Algiers, and Tripoli) of North Africa in the late 18th and early 19th centuries. At issue was the Barbary pirates' demand for tribute from American merchant vessels in the Mediterranean Sea. If ships of a given country failed to pay, pirates would attack the ship and take their goods, and often enslave crew members or hold them for ransom. When Thomas Jefferson became President he refused to pay tribute and sent a United States Naval fleet to the Mediterranean; they bombarded the various fortified pirate cities, ultimately extracting concessions of fair passage from their rulers. Both the administrations of Thomas Jefferson and James Madison undertook actions against the Barbary States at different times. Jefferson led the first, from 1801 to 1805, against pirates' cities in what are today Libya, Tunisia, and Algeria. Madison directed forces for the second war in 1815.