WordNet sense 1 (elected vice president and became 21st President of the United States when Garfield was assassinated (1830-1886)):

Chester A. Arthur, Chester Alan Arthur, President Arthur

WordNet sense 2 (a legendary king of the Britons (possibly based on a historical figure in the 6th century but the story has been retold too many times to be sure); said to have led the Knights of the Round Table at Camelot):

King Arthur