On May 18, 2025, Pope Leo XIV officially began his pontificate as the successor of St. Peter. On May 25, he celebrated Mass at the Archbasilica of St. John Lateran, the cathedral and local church of the Bishop of Rome, thereby commencing his pastoral ministry for the Diocese of Rome. The Archbasilica of St. John Lateran, located on the Caelian Hill in Rome, is known as “Omnium Urbis et Orbis Ecclesiarum Mater et Caput” — “The Mother and Head of all churches in the city and the world.” It was from here that Popes led the Universal Church until the Avignon Papacy.

The Lateran Basilica was constructed in AD 324 under the oversight of Emperor Constantine and consecrated by Pope Sylvester I. It was the first Christian basilica built in Rome. Though initially dedicated to Christ the Savior, it was later re-dedicated twice: once in the 10th century in the name of St. John the Baptist and again in the 12th century in the name of St. John the Evangelist. Today, its full name is “The Archbasilica of the Most Holy Savior and of Saints John the Baptist and John the Evangelist.”

Popes are enthroned as heads of the Universal Church in their capacity as successors of St. Peter, the first Bishop of Rome. However, the day-to-day pastoral administration of the Diocese of Rome is carried out by the Pope’s Vicar, currently Cardinal Baldisseri Reign.

Pope Leo XIV began his message as the head of the Diocese of Rome with the words, “The Roman Church is a continuation of a great history rooted in the witness of Sts. Peter and Paul and countless martyrs.” The designation of St. John Lateran Basilica as the “Mother Church of all churches in the world” prompts us to reflect on the maternal nature of the Church. Traits of motherhood such as compassion, willingness to sacrifice, and attentiveness should be reflected in churches around the world, the Pope said.