Answer
Alfonso Carlos, Duke of San Jaime was a Spanish Carlist pretender to the throne. He was born in 1849 and died in 1936. He was the son of Carlos, Duke of Madrid, and his wife, Maria de las Mercedes of Bourbon. Alfonso Carlos never married and had no children. He died without a successor, and the Carlist claim to the Spanish throne passed to his nephew, Jaime, Count of Barcelona.