Roman funerary customs were statuary and every Roman citizen had to properly bury the body of deceased person. Mausoleum was the most luxurious form of tomb and only the wealthiest citizens could afford that kind of final resting place. The imperial mausoleums have been proof of the emperor's power and his worship after his death. The first such mausoleum was built by Emperor Augustus. The building in the form of tumulus probably had the Etruscan origin. Emperor Trajan has not been buried in a mausoleum, but his column is a very important archaeological monument and it can not be excluded from this paper. Hadrian has built and modeled his mausoleum after Augustusus, and after several modifications throughout history, the mausoleum was converted into the present fort of St. Angelo. One of the greatest persecutor of Christians, Emperor Diocletian was buried in a mausoleum in his palace in Split. At a time when Christianity prevailed the Empire, the mausoleum was converted into a church of St. Domnius, which is the oldest cathedral in the world. Following the example of Diocletian, Emperor Galerius has bulit two octagonal type mausoleums in Gamzigrad near the city of Zajecar in Serbia. Maxentius has built himself a mausoleum in which he buried his son Romul. The first Christian Roman Emperor, Constantine the Great was buried in the church which was primarily mausoleum. Former Church of the Holy Apostles now has been converted into a mosque Fatih Camii.