(Diniz). Born Oct. 9, 1261, in Lisbon; died Jan. 7, 1325, in Santarém. Became king of Portugal in 1279.
Backed by the middle and lesser nobility and the towns, Denis I successfully fought the feudal aristocracy and increased the royal power. He limited the jurisdiction of the clergy, replaced the use of Latin in the royal courts with Portuguese, and increased the royal domain by revising the feudal land laws. He urged the peasants to develop wastelands, drain swamps, and plant forests and encouraged the development of mining and domestic and foreign trade; he also initiated Portuguese sea travel. In 1290 he founded a university in Lisbon. He patronized Portuguese literature and wrote poetry himself.