Arthur III (in Breton Arzhur III) (24 August 1393 – 26 December 1458), known as the Justicier and as Arthur de Richemont, is Lord of Parthenay and titular Count (Earl) of Richmond in England and for eleven months at the very end of his life, Duke of Brittany and Count of Montfort after inheriting those titles upon the death of his nephew.
