Between 1784 and I8l6, all four Barbary nations had captured and enslaved Americans. Generally the pirates treated the imprisoned Americans harshly, but the aid the United States forwarded to them alleviated much of their suffering. During this period the prisoner issue played an important role in formulating American foreign policy in the Mediterranean because of America's keen commercial interest in that region and its benevolent attitude toward its own citizens. In return, those captive Americans in North Africa supplied their government with valuable intelligence, and, after liberation, some continued to serve their country in the Mediterranean area.