Peter's main policies were concerned with restricting the political power of the great noble houses and expanding the powers of the crown. The country prospered under his rule, but not peacefully, as his laws interfered with the ambition of powerful nobles. The count of Barcelos, a personal enemy of the Duke of Coimbra (despite being half-brothers) eventually became the king's favourite uncle and began a constant struggle for power. In 1442, the king made 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, Peter had Afonso marry his daughter, Isabella of Coimbra, in 1445.