John Smith, who had earned the title "captain" while serving with the Hapsburg cavalry along the border between the Austrian and Turkish empires, recognized Jamestown's vulnerability after exploring the surrounding terrain during trade with Native peoples. In 1609, while president of the colony, he built a defensive position on this bluff above Gray's Creek so colonists could defend themselves against attacks from Algonquian Natives and against Spanish galleons some feared might try to drive them from the New World. According to Smith's Generall Historie, the fort was never completed because he was called back to Jamestown when rats infested the corn supply. The remaining two-foot-high earthworks are considered the oldest English structure in Virginia. In 1614, after John Rolfe married Pocahontas, Powhatan gave this tract of land to the couple. At the confluence of Gray's Creek and the James River, the town of Cobham was established in 1691, remained active during the 18th and 19th centuries, and has left remnants such as foundations, locks, broken china, and a long-barreled pistol that are sometimes uncovered in what is now farmland.