Pedro III of the Castilian Burgundy dynasty was born in 1400 as the son of Pedro II and his wife. After the early death of his father, he became king of Castile at the age of 18 years. Because of a decision of his father, his country was involved in the second Aquitainian War when he became king. But in 1424, the Cortes, the Castilian estates, protest the high costs and low results of the war. King Pedro was sorry about it, but had to leave the war,.