Its source is Heimrich, an Ancient Germanic name meaning "Home leader."
This boy's name is used in French.
Among the Norman barons who conquered England in 1066 were a number named Henri, the French version of the Germanic name Heimrich.
Anglo-Saxon tongues could not easily negotiate the French nasalized ''en'' and the characteristic ''r,'' so during of the Middle Ages Henri was rendered as Harry in spoken English. The English spelling, however (following Latin and French), was Henry.
Over time, the name's spelling began to influence the way it was said. Eventually, Harry, once the primary English pronunciation of the name, joined ranks with Hank and Hal as one of Henry's nicknames.