The Mausoleum

From Tomb to Church

In the southwestern part of the palace, there is a circular building originally constructed as the Mausoleum of Diocletian. After his death, the mausoleum was converted into a Christian cathedral during the Middle Ages, now known as the Cathedral of Saint Domnius. The reason why the brick-built palace still stands today is explained in Friedrich Idam's podcast "opus cementitium," discussing Roman concrete.

For further information about the mausoleum, you can follow this link.