The Palazzo San Callisto (also known as the Palace of Saint Callixtus) is a small palace in Rome and one of the extraterritorial Properties of the Holy See. The Palazzo is located in the Piazza di San Callisto, one of the areas of the Holy See regulated by the 1929 Lateran Treaty signed with the Kingdom of Italy. As such it has extraterritorial status. The Palazzo San Callisto was named in honour of Pope Callixtus I and is now home to: The Pontifical Council Cor Unum The Pontifical Council for the Family The International Catholic Charismatic Renewal Services. In 1990, the Palazzo was placed on the UNESCO World Heritage Register .