Serbia, city of Sremska Mitrovica: Interior of roofed archeological site of Imperial Roman Palace of antique Sirmium (Serbian: Carska palata Sirmijuma), with mosaics, reception area (front, right), and heating system around atrium (back); background Roman city of Sirmium: Sirmium (city of Sremska Mitrovica, Serbia); background Sirmium: On crossroads from West to East and North to South and on the banks of Sava river (Latin: Savus), Roman Sirmium, conquered 13 – 9 BC, became one of the most important towns of Late roman Empire. In 103 AD, it became capitol of Roman province of Lower Pannonia. In 293 AD, when the Empire was split into four parts (tetrarchy) under emperor Diocletian, Sirmium became even capitol of the empire, along with today’s Trier (Germany), Medilanum (today: Milan, Italy), and Nicomedia (Turkey) and “famous and populous mother of cities”. Historians still doubt, weather Sirmium in 3rd and 4th century AD really reached a number of 100 000 inhabitants. Most probably, it arrived at present size of Sremska Mitrovica (41600 inhabitants). Emperor Trajan started his campaign against Dacians, here, and Emperor Galerius fist took seat here. Minimum 5 (others count 10) Roman Emperors were born in or around Sirmium: Trajan Decius, Aurelian, Probus, who invented viniculture in the surroundings, Maximinianus Herculius and Gratian. Further emperors resided here: Domitian, Marcus Aurelius (from 170 – 180), who probably died here, Septimius Severus, Maximinus Thrax, Claudius II Gothicus, Diocletian and usurpers Ingenuus and Regalian. Under Diocletian, Licinius, Constantine the Great, Constantius II, Julian, Valentinian I, Gratian and even Theodosius seat of government was placed in this prosperous city. And there is the Christian Sirmium, place of the two synods (357 – 359 AD), with its first bishop Irenaeus, who was decapitated on Roman Sava Bridge, in 304 AD. 1957, excavations were started at Sirmium Imperial Palace, a basilica, which was discovered by chance du, Image: 278129456, License: Rights-managed, Restrictions: , Model Release: no, Credit line: Profimedia, AKG