https://en.wikipedia.org/wiki/Barbary_Wars

The Barbary Wars was a series of conflicts that culminated in two wars fought at different times over the same reasons between the United States, Sweden , and the Barbary states (the de jure possessions of the Ottoman Empire, but de facto independent, Tunis, Algiers, and Tripoli) of North Africa in the late 18th and early 19th centuries. The Swedes having been at war with the Tripolitans since 1800 were eventually joined by the Americans.[2] 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.

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https://en.wikipedia.org/wiki/Barbary_slave_trade

The Barbary slave trade refers to the slave markets that flourished on the Barbary Coast of North Africa, or modern-day Morocco, Algeria, Tunisia, and western Libya, between the 16th and middle of the 18th century. These markets prospered while the states were nominally under Ottoman suzerainty, but in reality they were mostly autonomous. The North African slave markets traded in European slaves .

The Barbary Coast. The European slaves were acquired by Barbary pirates in slave raids on ships and by raids on coastal towns from Italy to Spain, Portugal, France, England, the Netherlands, and as far as Ireland and Iceland.

For centuries, large vessels on the Mediterranean relied on European galley slaves supplied by North African and Ottoman slave traders.

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In 1785 when Thomas Jefferson and John Adams went to London to negotiate with Tripoli's envoy, Ambassador Sidi Haji Abdrahaman, they asked him what right he had to take slaves in this way. He replied that the "right" was "founded on the Laws of the Prophet, that it was written in their Koran that all nations who should not have answered their authority were sinners, that it was their right and duty to make war upon them wherever they could be found, and to make slaves of all they could take as prisoners, and that every Mussulman who should be slain in battle was sure to go to Paradise".[7]

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