For 10 points, give this name shared by two nineteenth-century emperors of Brazil.
One king of this name was restored to the throne of Castille by Edward the Black Prince following the battle of Najera, and fought a namesake war with a king of Aragon with the same name. Another king of this name uttered the Cry of Ipiranga after his father John VI departed for Europe. Yet another king of this name fought the Paraguayan War of 1865 to 1870, and issued the Golden Law which abolished slavery in his country. For 10 points, give this name shared by two nineteenth-century emperors of Brazil.
One king of this name was restored to the throne of Castille by Edward the Black Prince following the battle of Najera, and fought a namesake war with a king of Aragon with the same name.
{Pedro} [or {Peter}]