Alfonso de Borja, also known as Pope Callixtus III, was a Spanish cardinal born in 1378 in Xàtiva, Spain. He became pope in 1455 and is known for his efforts to strengthen the Catholic Church during a time of political turmoil in Europe. His papacy was marked by attempts to launch a crusade against the Ottoman Empire. During his time as pope, Alfonso de Borja focused on promoting the interests of the Borgia family and enhancing the power of the papacy. He also initiated the beautification of Rome and supported various artistic projects, contributing to the cultural development of the city.