Christianity’s First Cathedral

St. John Lateran was Christendom’s mother basilica and home of the Popes for 1,000 years.


San Giovanni in Laterano (St. John Lateran) was Christendom’s earliest Papal basilica. Commissioned by Rome’s first Christian Emperor, Constantine the Great, it became the Popes’ official residence and cathedral for the first millennium of Christian history. Today, standing before the basilica’s ponderous eighteenth-century facade, assailed by ear-splitting Roman traffic on every side, we can hardly imagine this as the cradle of Christianity. A visitor should glance upwards. Towering against the (usually) cobalt-blue sky, a seven-metre-high statue of Christ triumphantly displays the Cross of Redemption. The Saviour is flanked by Sts. John the Baptist and John the Evangelist, as well as Doctors of the Eastern and Western Churches.

‘Omnium urbis et orbis ecclesiarum mater et caput’ – this inscription from the basilica’s earlier facade, now covering the space between the portico and the loggia, declares that the Pope and the Emperor wished this basilica to be considered the first and mother of all churches. It was to Jesus the Saviour that Constantine dedicated the original church, confirming Christ’s superiority over the Capitol’s pagan gods and assuring the worldwide expansion of the Christian religion.


With the ascent of Constantine as Emperor of Rome (306-307), the days of bloody Christian persecutions came to an end. Placed at first on an equal footing with paganism, Christianity soon became the official religion of the Roman Empire.

Constantine was the son of Constantius Chlorus, Roman Emperor (Caesar) of the West (305-6), and Helena, a woman of obscure origins, whose fervent conversion to Christianity and alleged finding of the True Cross in Jerusalem won her sainthood. After defeating his rival Maxentius, son of the earlier Emperor Maximian (286-305), at the Milvian Bridge in Rome in 312, Constantine established himself as the undisputed ruler of the Western Empire.

The night before this battle, Constantine’s earliest biographer, Eusebius, tells us, the Emperor saw a cross of light in the heavens and the words: ‘By this sign you shall conquer.’ His soldiers went into battle bearing the Christian monogram on their shields, rather than the Roman eagle, and with a standard of Christ’s cross carried before them. From that time, as he won battle after battle, and consolidated his rule over the Empire in the East and West in 324, the Emperor claimed to be fighting in Jesus’s name, as the champion of the Christian faith.

The Edict of Milan (313) secured Christians’ freedom and legal recognition. By imperial edicts, Constantine restored Christians’ property and strengthened the Church hierarchy (without giving too much offence to Rome’s influential pagans). He called the Council of Nicaea, which denounced the Arian heresy and promulgated the Nicene Creed.

Was Constantine a pious visionary or an ambitious opportunist? Historical opinions differ. Biographers report his late-in-life remorse for ordering the deaths of his wife Fausta, son Crispus (by his first wife, Minerva), and several other relatives. It was only when he lay upon his deathbed that the Emperor asked to be baptized. At the age of sixty-four he died, clad in the white garment of a new convert.

The first Christian Emperor had ordered basilicas built over the cellae memoriae marking St. Peter’s, St. Paul’s, and other martyrs’ tombs. and he donated his personal property, received in dowry from his wife, for the first Papal cathedral and residence in Christian history. So begins the story of St. John Lateran.


Excerpt from Hager, June. Pilgrimage: A Chronicle of Christianity Through the Churches of Rome.  (Weidenfeld & Nicolson: London), 1999.

We will be going to visit the Basilica of St. John Lateran in our upcoming Journey Toward the Face of Christ pilgrimage this coming May/June 2022.