Roman Catacombs historical timeline

A community that could not bury its dead in the usual way dug its own cemetery, and the Church has been running it ever since.

Chronology

1. Second half of the 2nd century — the Christians of Rome begin to dig their own community cemeteries, the places known today as catacombs. Structural impact: corridors cut into soft rock outside the city. What you see today: the beginning of the network.
2. Early 3rd century — the deacon Saint Callixtus is placed in charge of the cemetery's administration by Pope Zephyrinus. Structural impact: the complex acquires central management. What you see today: the name of the catacombs.
3. 3rd century — San Callisto becomes the official cemetery of the Church of Rome. Structural impact: expansion from family burial into an institution. What you see today: the scale — about half a million Christians, among them dozens of martyrs and sixteen pontiffs.
4. 3rd century, continued — the Crypt of the Popes takes shape as the heart of the complex, alongside the Crypt of Saint Cecilia, the cubicles of the sacraments, the region known as that of Pope Miltiades and the region of Saint Caius and Saint Eusebius. Structural impact: chambers cut off the corridors. What you see today: the visit route.
5. Since antiquity — the catacombs remain the destination of continual pilgrimages on account of the many martyrs buried there. Structural impact: continuous access, which is why they survived. What you see today: a site that was never lost.
6. 1930 — the reception of pilgrims and the guided visit to the catacombs open to the public are entrusted to the Salesians of Don Bosco. Structural impact: none. What you see today: who shows you round.
7. Today — the complex is the property of the Administration of the Patrimony of the Apostolic See, with government, custody and conservation entrusted to the Pontifical Commission for Sacred Archaeology, a body of the Holy See. Structural impact: none. What you see today: why the rules are the Church's rather than the city's.