Francisco Castelló was a Spanish chemical engineer and devout Catholic activist born in Alicante in 1914. A member of Catholic Action and the Federation of Young Christians of Catalonia, he was known for his strong faith and spirited personality. During the Spanish Civil War, he was drafted into the military and subsequently imprisoned in Lleida. Following false accusations of fascism, he was sentenced to death by a people's court. He was executed on September 29, 1936, while shouting his devotion to Christ.