On the place of today's municipality was in antiquity the Roman castrum Drobeta. The destruction of the fort of Drobeta occurred in the first half of the fifth century, in the context of barbarian invasions and the collapse of the Western Roman Empire.
The Severin Fortress was built by the Hungarian Kingdom as a strategic military center established against the Bulgarian Empire of Vidin. The Latin church inside the medieval fortress was placed under the patronage of Saint Severin of Noricum, from which, it seems, comes the name of the settlement. The Severin Fortress, built by the Hungarian king Ladislaus I (1040-1095) as a fortress against the Pechenegs and Cumans present in the region, will be the cause of permanent claims and a series of frequent wars between the Hungarian, Bulgarian and Wallachia crowns, starting with Litovoi, Barbat, and Basarab I. In a first period, the city of Severin is an objective of political, economic and religious dispute between Christian princes.
In 1233 the fortress of Severin (built by Ladislaus I) is transformed by Andrew II (King of Hungary between 1205 -1235) into the Citadel. Thus is born the Banat of Severin organized since 1228, a region founded at the borders of the Roman-Bulgarian Empire to guard the border of the Hungarian Kingdom and restore the influence of the Latin Church in the region.
The Banat of Severin, Banatus Zewriniensis, "Terra Zeurino" or "The Land of Severin", included the Caras with a strip of Transylvania, the hateg country, the land of Amlas and a neighboring part of Oltenia (Mehedinti, a part of Gorj and Valcea, stretching on both sides of the mountains) from the Danube to the Olt River. The first Ban of Severin, Luke, is mentioned in 1233, during the time of King Andrew II of Hungary. The year 1233 ? in resonance with the year 1833 when the new modern city was registered ? can be considered as the official date of birth of the fortress.
Mircea the Old also bore the title of Ban de Severin, and in 1406, in the face of the Ottoman danger, he concluded an alliance treaty with Sigismund I of Luxembourg (1387-1437) right in the city of Severin.
After the destruction of the Severin Fortress, giving it the emblematic name of mourning Cerneti ("cerniti") the Severinians founded another settlement more protected from the Turkish incursions about 6 kilometers to the north-east of the old burnt fortress. Until the modern reconstruction of Severin, Cernetiul, which around 1602 was an estate of the Buzesti brothers, will be the administrative and commercial capital of the Mehedinti region, being used by both the Russians and the Austrians.
Until 1918, Turnu Severin will be the western gate of Romania. After 1900, the industry and capital of Severin continued to diversify at an accelerated pace.