King John II at the time was very interested in curbing the seigneurial power of the nobility and concentrating his power. Fernando (supported by the King's cousin, the Infante Diogo, Duke of Viseu) protested and conspired with Isabella I of Castile, which resulted in his being accused of treason by King John II, when the Duke's correspondence was intercepted by the King's spies. By order of the King, the Duke's properties and possessions were confiscated, and his residence in Guimarães continued to be looked after as Crown property, even as Duke Fernando was judged and executed on 20 June 1483 in Évora. The house was cared for by carpenters João Domingos, and later his son-in-law Afonso Anes, who were appointed to head the renovations of the property by John II.