He received a very good education from French and Portugese
          scholars. However, in 1277 his rebellion against his father caused a
          civil war, sorrow for which hastened his father's death in 1279. Diniz
          now became King of Portugal but his legitimacy was immediately
          disputed by his younger brother Alfonso, who had been born after the
          regularization of their parents' marriage. They came to a compromise
          leaving Diniz as the undisputed king.
              Diniz founded the University of Lisbon which was later moved to
          Coimbra. He was king for about forty-six years, a reign that brought
          comparative peace to Portugal. In his efforts he became known by the
          nickname of 'the Labourer or farmer'. He strengthened the major cities
          and built more towns and as well writing poetry. He married a Princess
          of Aragon who later was canonized as St. Isabel of Portugal, and by
          her became the father of a son and a daughter.
              He had many affaires and fathered many children whom he favoured
          greatly. His sister, Abbess of Las Huelgas, became notorious for her
          love affair with a carpenter, producing a son who later became Master
          of the Order of Calatrave but was beheaded by Pedro the Cruel of
          Castile. Diniz's favouring his illegitimate sons caused a bitter
          dispute with his legal son and heir, Alfonso, who took up arms against
          him and marched on Lisbon. However, the Queen moved between the two
          armies and forced her husband to make peace with their son, which
          lasted until the death of Diniz in January 1325.
 

Source: Leo van de Pas