The capture of "Philadelphia" and its crew also motivated President Jefferson's decision to send William Eaton, a former Army officer, known for his brash and defiant diplomacy, to Tripoli in 1805 to free the 300 American hostages in what was the first U.S. covert mission to overthrow a foreign government. William Eaton established a group of about 20 Christian (eight of whom were U.S. Marines) and perhaps 100 Muslim mercenaries to begin the takeover of Tripoli starting with Derna. He managed to trek with the small detachment of Marines led by Presley O'Bannon and his mercenary force over 500 miles. Supported at sea by Isaac Hull, Captain of , in an effective "combined operation", Eaton led the attack in the Battle of Derna on 27 April 1805. The town's capture, memorialized in the "Marines' Hymn" famous line "to the shores of Tripoli" and the threat of further advance on Tripoli, were strong influences toward peace, negotiated in June 1805 by Tobias Lear and Commodore John Rodgers with the Pasha of Tripoli.