Operating out of ports in North Africa, Barbary pirates and privateers preyed on commerce throughout the western Mediterranean, capturing ships and enslaving their crews. In response to attacks on American shipping, President Thomas Jefferson directed the Navy to conduct operations against the Barbary States from 1801 to 1805. The treaty that ended the fighting did not eliminate its underlying cause. The continued capture of American shipping and merchant seaman led to a second military conflict with the Barbary States in 1815. Participation by Columbia students and alumni in these conflicts remains unconfirmed.