The Holy Four Crowned Martyrs are actually 9 martyrs, there seems to be uncertainty over their names, and they have two separate feast days, one in August for the first four and one on November 8 for the second 5 who were sculptors martyred by Diocletian because they wouldn’t sculpt pagan idols.
The Basilica di Santi Quattro Coronati in Rome,which was first built near the execution site in the 300s and then rebuilt in the 1100s after being destroyed by invaders, is named after them and is one of the titular churches of Rome. Its most famous Cardinal was Pope Benedict XV before he became Pope.
It’s off the beaten path in Rome and thus really interesting to visit as there are very few tourists around.
Super quiet except for some kids playing ball. The basilica looks like an old medieval castle up on a hill. You can hear the Augustinian nuns sing Vespers if you go at a certain time in the evening.