Complex sentence: During the American Revolution Clayton served in the Bohemia Manor militia of the Maryland Line, and it is believed he was commissioned a major and was an aide and surgeon to General George Washington at the Battle of Brandywine and Valley Forge.
Split into simpler sentences: During the American Revolution Clayton served in the Bohemia Manor militia of the Maryland Line, where he had been commissioned a major. He was also an aide and surgeon to General George Washington at the Battle of Brandywine and Valley Forge.