count his uncle Afonso the first Duke of Braganza. With this title and its lands, he became the most powerful man in Portugal and one of the richest men in Europe. To secure his position as regent, Pedro had Afonso marry his daughter, Isabella of Coimbra, in 1445. But on 9 June 1448, when the king came of age, Pedro had to surrender his power to Afonso V. The years of conspiracy by the Duke of Braganza finally came to a head. On 15 September of the same year, Afonso V nullified all the laws and edicts approved under the regency. In the following year, led by what were later discovered to be false accusations, Afonso declared Pedro a rebel and defeated his army in the Battle of Alfarrobeira, in which his uncle (and father-in-law) was killed. Invasion of Morocco Afonso V then turned his attentions to North Africa. In the reign of his grandfather John I, Ceuta had been conquered and taken over from the king of Morocco, and now the new king wanted to expand the conquests. The king's army conquered Alcácer Ceguer in 1458 and Arzila in 1471. Tangiers, on the other hand, was won and lost several times between 1460 and 1464. These achievements granted the king the nickname of the African or Africano. The king also supported the exploration of the Atlantic Ocean led by prince Henry the Navigator but after Henry's death in 1460, he did nothing to continue Henry's work. Administratively, Afonso V was a passive king. He chose not to pursue the revision of laws or development of commerce, preferring instead to preserve the legacy of his father Edward and grandfather John I. In 1469, King Afonso V of Portugal granted Fernão Gomes the monopoly of trade in the Gulf of Guinea. In 1452, Pope Nicholas V issued the papal bull Dum Diversas, which granted Afonso V the right to reduce "Saracens, pagans and any other unbelievers" to hereditary slavery. This was reaffirmed and extended in the Romanus Pontifex bull of 1455 (also by Nicholas V). These papal bulls came to be seen by some as a justification for the subsequent era of slave trade and European colonialism. Castile When the campaigns in Africa were over, Afonso V found new grounds for battle in neighboring Castile. On December 11, 1474, King Henry IV of Castile died without a male heir, leaving just