Jonathan Arnold was born in
Gloucester, Rhode Island on December 3, 1741 (
Old Style December 14), the son of Josiah Arnold and Amy (Phillips) Arnold. He trained for a career in medicine and practiced as a physician in
Providence. In 1774, he became a charter member of the Providence Grenadiers militia unit, and until 1776 he commanded a company with the rank of
captain. In 1776, Arnold was elected to the
Rhode Island General Assembly, where he authored the May Act that repealed the requirement for government officials and militia officers to swear an oath of allegiance to England. At the start of the
American Revolution, Arnold joined the
Continental Army as a surgeon. During the war, he was head of the military hospital in Providence. He was elected as a Delegate to the
Congress of the Confederation in 1782, and served until 1783. While he was a member of Congress, the body voted in secret to arrest
Luke Knowlton and Samuel Wells of
Brattleboro in the
Vermont Republic on suspicion of communicating with the British in Canada. They fled before they could be detained, but returned to Brattleboro after the end of the Revolution. Arnold was accused of warning Knowlton and Wells prior to their arrests, which he denied, but fellow members of Congress including
James Madison did not believe his denial. ==Later life==