​MONTAUBAN, ARTHUR DE (d. 1479), French magistrate and prelate, belonged to one of the great families of Brittany. To satisfy a private grudge against Gilles, brother of Duke Francis II. of Brittany, he intrigued to such good purpose that Gilles was arraigned for treason, and finally assassinated in prison in 1450. When Montauban's duplicity was discovered he was deprived of his office of bailli of Cotentin and banished. He then turned monk, and through the support of his brother, John de Montauban (1412–1466), Louis XI.'s favourite, obtained the archbishopric of Bordeaux in 1468. He died in Paris on the 9th of March 1479.