Prince Balthasar Charles (1629 - 1646). Balthasar Charles, Prince of Asturias, Prince of Girona, Duke of Montblanc, Count of Cervera, and Lord of Balaguer, Prince of Viana was heir apparent to all the kingdoms, states and dominions of the Spanish monarchy until his death. The only son of King Philip IV of Spain and his first wife, Elisabeth of France, he was baptized on November 4, 1629 in the Parish of San Juan, Madrid. His godparents were Infanta Maria Anna and Infante Charles, aunt and uncle of the newborn; Inés de Zúñiga y Velasco, Countess of Olivares sat on a crystal throne during his baptism, which was said to be the most precious jewel she had seen. The Countess of Olivares, who was also chief lady-in-waiting to the Queen, worked as a governess to the prince, which gave rise to comments about the control that the Count-Duke of Olivares had on the heir. On 7 March 1632, he was sworn in before the nobility of Castile as His Majesty's Heir and Prince of these kingdoms of Castile and Leon, and others that are subject to these Crowns, united and incorporated, in a ceremony held at the Monastery of San Jerónimo el Real of Madrid. His father soon began diplomatic efforts to seek a bride: Archduchess Mariana of Austria, daughter of Holy Roman Emperor Ferdinand III and his paternal aunt, Maria Anna, and therefore his cousin, being chosen. Another cousin, the daughter of his mother's sister, Henrietta Maria and her husband, King Charles I of England, Mary, Princess Royal, was also proposed as a potential bride-but was turned down on grounds of religion. After the Catalan revolt of 1640, Philip IV tried to win over Aragon to raise money and men for the new war front. One of the steps taken towards this end was to bring the Prince Balthasar Charles to be sworn as crown prince of the Kingdom of Aragón. The oath was held on 20 August 1645, when the prince was sixteen years old, in the Cathedral of the Savior, Zaragoza. This titled him as Prince of Gerona, Governor General of Aragon, Duke of Montblanc, Count of Cervera and Lord of the City of Balaguer. Meanwhile, on 13 November of that year, Balthasar Charles was also sworn as heir to the Kingdom of Valencia. In April 1646, Philip IV, wanting his son to be sworn in as heir apparent to the throne of Navarre, as he had been in Aragon the previous year, moved with him from Madrid to Pamplona, where, after recognizing the privileges of the kingdom of Navarre, the ceremony was solemnly celebrated on 3 May 1646. After the ceremony, the royal family moved to Zaragoza. On October 5, the eve of second anniversary of the death of Queen Elisabeth, Philip IV and Balthasar Charles attended Vespers that night in her memory. That evening, the prince was ill and the next day, Saturday October 6, he had to stay in bed while the king went to the funeral. The disease, smallpox, spread rapidly, and on Tuesday, October 9, at 8 in the morning, the Archbishop of Saragossa gave him the Last Sacraments. It is said that the Host was exhibited until 3 o'clock, when it became a general procession to the Convent of Jesus, which then proceeded to Our Lady of Cogullada and brought in procession to the altar of La Seo where it was surrounded by candles and prayers. At 9 pm that same day, October 9, Prince Balthasar Charles died. His remains were kept in Zaragoza until the night of October 16, when they were transferred to the Monastery of San Lorenzo de El Escorial. The king fell into a deep unease as noted in a letter his spiritual advisor, Sister Maria de Agreda:The prayers did not lift the spirits of our Lord for the health of my son enjoying his glory. Not agreeing owed him or us otherwise. I'm in the state that you can judge, for I have lost a child I had, so that you you saw him, I really encouraged him much in the midst of all my cares have offered to God this blow, which I confess I have pierced the heart and in this state do not know if dream or truth is what happens for me.