What Lies Under the Duomo of Milan?

After being closed due to COVID-19 for months, the cathedral opened to tourists on May 29th. Of course, social distancing and other measures have been put in place but it is open nonetheless. No visit to Milan is complete without visiting this iconic site. Its towering gothic spires decorated with hundreds and thousands of statues are impressive. Step into the church and you’re immediately struck by the grandeur, beauty and size of the towering, sequoia size marble pillars. The Duomo of Milan was definitely built to impress. You can learn more about visiting the church in my previous post.

Construction began in 1386 and wasn’t complete until 1965. Yes, do the math. It took 579 years to complete. Incredible! After moving here I wanted to find out what was there before the duomo was built? A field? Houses? Was it a blank slate? As a christian I wondered if there had been another church on the same site. I’m a bit of history nerd so I want to know the details. I began to learn and every visit to the duomo revealed new and amazing facts about the history of Milan. 

Much to my surprise there were five different buildings on the site where the Duomo now stands:


Directly under Milan’s Duomo sits the remains of Santa Maria Maggiore (originally named Basilica Vetus), the first Christian church in Milan, which was built in 314 AD (!). One year prior the Edict of Milan was signed by emperors Constantine and Licinius making Christianity legal throughout the Roman Empire. Milan, then known as Mediolanum, was at that time the capital of the Roman Empire. The church was destroyed in 1386 to make room for the new and improved, massive Duomo. Nothing remains of the church today. For 1,072 years Santa Maria Maggiore stood welcoming worshipers. Thousands, probably millions of people walked through its doors. Coming from a young country, it amazes me that there has always been a church in the same spot for 1,706 years. It’s absolutely mind boggling.

A map of the outline of the Duomo (in gray) and the previous buildings.


The baptistery of San Stefano Alle Fonti was built in 313 AD, yes, the same year as the Edict of Milan. It was located just outside of Santa Maria Maggiore. The remains of the baptistry can still be seen today. Outside the chancel, where folks line up to take the elevator to the top of the Duomo, there is an area to the left which is open to the public for free. It’s pretty unremarkable, a crumbling, stoney pool, not much to look at but its history is so significant. I was really surprised that there is no signage, no pomp given to this paleochristian site. This is where bishop Ambrose, the great defender of the faith, was baptized in 374. 

Baptistry of San Stefano Alle Fonti


Santa Tecla (originally named Basilica Maggiore) was built in 350 AD by Constantine’s son. It was destroyed in 1461 to make way for the new Duomo. The partial remains of the church lie under what is today Piazza Duomo. In fact, it was in the 1960s when the metro station and line were being built that the remains were discovered. As construction crews dug up the piazza to create the metro station they stumbled across this paleochristian site. Unlike Santa Maria Maggiore, some of the remains of Santa Tecla are still visible. At the narthex of the church is what is called the “archeological area” which included in the price of the “Cultural Pass” ticket. 

The discovery of Santa Tecla and the baptistry of San Giovanni Alle Fonti in the 1960s.


Next to Santa Tecla sat its corresponding baptistry, San Giovanni Alle Fonti, built in 378 AD. It was here that the bishop of Milan, Ambrose, baptized Augustine of Hippo on Easter Sunday 387. The baptismal with its mosaics can still be seen today. It’s part of the “archeological area” that is open to visitors. 

The baptistry where Ambrose baptized Augustine@


Not only does the Duomo sit atop the ruins of some of the earliest paleochristian sites in the world, it also sits on the Roman ruins of the Temple of Minerva. In fact, Santa Tecla was built with pieces of the Roman temple. As Christianity spread through the empire, pagan temples were used as building material for new Christian churches. The exact date of the construction of the temple is vague. We do know that Milan, or as it was known then, Mediolanum, was conquered by the Romans in 222 BC so it’s safe to assume the temple was built sometime after.

It’s an incredible place with an incredible history.

A video of the archeological area open to visitors.
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  1. Thank you for this story. I want to go back to Milan sooner or later and take pictures from the rooftop; and along the way know more about it.

    This is very interesting and so well explained.

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