In 1735, two years after James Oglethorpe founded Savannah, he sent a detachment of troops to explore the upper Savannah River. He gave them an order to build a fort at the head of the navigable part of the river. The expedition was led by Noble Jones, who created a settlement as a first line of defense for coastal areas against potential Spanish or French invasion from the interior. Oglethorpe named the town in honor of Princess Augusta, the mother of King George III and the wife of Frederick, Prince of Wales. Oglethorpe visited Augusta in September 1739 on his return to Savannah from a perilous visit to Coweta Town, near present-day Phenix City, Alabama. There, he had met with a convention of 7,000 Native American warriors and concluded a peace treaty with them in their territories in northern and western Georgia. Augusta was the second state capital of Georgia from 1785 until 1795 (alternating for a period with Savannah, the first).