The Muslim pirates had justified their attacks on Christians for centuries as an important element of Jihad. It was referred to as al-jihad-fil-babr or holy war at sea and it was a community of seamen or ta’ifa, it was an integral part of a holy war against the Christian infidel. This form of piracy provided the pirates with their greatest military heroes.2
There were two concepts involved, Dar al Islam or “house of peace” and Dar al-harb or “house of war”. The Americans were not paying tribute to the Barbary Pirates, so this placed them under the house of war and allowed them to become prey to piracy. Until they signed a treaty and tribute was exacted from them, they would remain victims of jihad. Once they were captured, the ship and its cargo were seized and the men were often sold into slavery.
In this jihad all captives were prisoners of war and were subject to slavery but the outcome for prisoners of war was: death, ransom, exchange, taxation, release, and enslavement. In the Barbary states slavery was usually the choice. “Islamic law, piously laid down: (slavery is) a humiliation and a servitude caused by previous unbelief and having as its purpose to discourage unbelief. From such opinions the Barbary pirates were able to legitimize outright slave raids.3
The British government encouraged this form of piracy, and during the Revolution, American colonial shipping in the Mediterranean was no longer no longer protected by the British Navy. In fact, the British allowed this assault on American shipping to keep them out of the Mediterranean so as to reduce competition in trade. Prior to this the British provided passes honored by the Barbary pirates simply because they feared the British navy, the most powerful navy in the world at the time.