Thomas Eaton Root, a North Carolina businessman, had spent his life with Rembrandt Peale’s portrait of his ancestor William Eaton when a sudden turn of events ignited his interest in the picture: his son, Tom Root, Jr., went to the Persian Gulf with the 66th Armored Brigade. Nearly two centuries earlier the man in the picture had fought in the same part of the world. With the kingdom of Tripoli at war with the infant United States, Eaton, as “Navy Agent to the Barbary States,” raised a band of 650 Arab, Greek, and Italian mercenaries. Jumping off from Alexandria in 1805, he led his scruffy coalition force and 11 U.S. Marines toward the enemy stronghold of Derna, five hundred miles away across what is today the Libyan Desert. After a six-week epic of thirst and near-mutiny, they reached their goal and stormed it, giving America its first victory on foreign soil and the Marines the second line of their hymn. When Mr. Root sent us a photograph of Eaton’s portrait early last year, he wrote, “Tom, Jr., is a wonderful son and an extraordinary young man. I prayed for peace; but now that we are at war, I hope that we will be as victorious as his great-great-great-great-grandfather.”