Fritz originated as a German nickname for Friedrich, or Frederick (der alte Fritz was a nickname for King Frederick II of Prussia and Frederick III, German Emperor), as well as for similar names including Fridolin. Fritz was also a name given to German troops by the British and others in the first and second world wars, equivalent to Tommy, as the British troops were called by German and other troops. Other common bases for which the name Fritz was used include the surnames Fritsche, Fritzsche, Fritsch, and Frisch(e).
Count Fritz von Tarlenheim , a character in Anthony Hope's "The Prisoner of Zenda," and it's sequel, "Rupert of Hentzau." Most notably played by David Niven in the 1937 version of "The Prisoner of Zenda."