1913 Our earliest battles with Islamic Terrorists
was back in the 18th century. Thomas Jefferson and John Adams faced the problem long before Bill Clinton and George Bush. The Islamists reasons then were not much different than today--we’re infidels and need to be either slaves or slain.
“Take, for example, the 1786 meeting in London of Thomas Jefferson, John Adams, and Sidi Haji Abdul Rahman Adja, the Tripolitan ambassador to Britain. As American ambassadors to France and Britain respectively, Jefferson and Adams met with Ambassador Adja to negotiate a peace treaty and protect the United States from the threat of Barbary piracy.
These future United States presidents questioned the ambassador as to why his government was so hostile to the new American republic even though America had done nothing to provoke any such animosity. Ambassador Adja answered them, as they reported to the Continental Congress, "that it was founded on the Laws of their Prophet, that it was written in their Koran, that all nations who should not have acknowledged 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 Musselman who should be slain in Battle was sure to go to Paradise."
There's much more on this topic at America’s earliest terrorists