Brother Jonathan: a nickname for an American in the time around the Revolutionary War, mostly used by the British
This term is said to have originated with George Washington, who supposedly first applied it to the governor of Connecticut, Jonathan Trumbull. When General Washington and his staff were puzzling over how to get the arms and supplies they needed, Washington remarked, "We must consult Brother Jonathan on the subject." The name caught on and Brother Jonathan became the personification of the shrewd New Englander (if you were an American) or an unsophisticated yokel (if you were British).
Brother Jonathan was in widespread use in the burgeoning republic, although eventually replaced with the still-popular Yankee.