Santa Costanza is an ancient structure in Rome with a fascinating history. Originally built by Emperor Constantine, who ruled from 272 to 337 AD, this building was designed as a mausoleum for his daughters, Constantina and Helena. It once formed part of a larger cemetery complex, and traces of that area are still visible today.
Over time, the mausoleum underwent a significant change. In the year 1254, it was consecrated as a church and dedicated to Constantina after she was declared a saint. Architecturally, Santa Costanza stands out because of its circular plan. An inner arcade, supported by pairs of sturdy granite columns, creates an elegant and timeless interior space.
One of the most remarkable features of Santa Costanza is its collection of mosaics dating back to the 4th century. These ancient artworks adorn the interior and capture scenes and patterns from early Christian art, offering a rare glimpse into the artistic traditions of the period.
Source - https://en.wikipedia.org/wiki/Mausoleum_of_Constantina