The Ancient Thracian and Roman settlement and fortress of Sexaginta Prista (meaning “Port of the Sixty Ships") in today’s Bulgarian Danube city of Ruse was built on top of an earlier Ancient Thracian settlement. Archaeological research has proven that the Sexanginta Prista Fortress was originally an Ancient Thracian settlement existing as early as the 3rd century BC. In fact, the hill where the settlement is located was a Thracian shrine for performing cult rituals which remain unknown to this day. There the Bulgarian archaeologists have discovered hundreds of Ancient Thracian ritual pits dating to the 1st century BC-1st century AD, of which about 50 have been studied. The archaeological discoveries from the Thracian ritual pits include pottery vessels, bronze artifacts, coins, bones; a unique richly decorated zoomorphic vessel depicted an eagle’s head as well as several fibulas. Other archaeological findings include an Ancient Thracian jug from the 2nd-1st century AD containing organic matter from domestic animals, an ancient ceramic vessel from the Greek island of Rodos dated to the 3rd century BC, household vessels, and transportation vessels, which are taken to mean that the settlement had a well developed trade.
The first written account about the Fortress of Sexaginta Prista comes from “Geography", the 2nd century AD work of Greco-Egyptian ancient geographer Claudius Ptolemy (ca. 90-168 AD). The city was also mentioned as Sexantapristis in the so called Antonine Itinerary (Itinerarium Antonini Augusti, “The Itinerary of Emperor Antoninus"). The name of Sexaginta Prista has been compared to the name of a Roman port on the Italian Peninsula meaning “100 chambers" because one hypothesis about its name has it that in Roman times Sexaginta Prista (today’s Ruse in Bulgaria) had 60 dock spots for Roman ships. Another hypothesis claiming to be based on all available historical sources has it that the name of the Sexaginta Prista Fortress stems from events at the end of the 1st century AD during Roman Emperor Domitian’s (r. 85-89 AD) wars with the Dacians, the powerful Thracian people living north of the Danube River. Back then, an entire Roman legion consisting of 6,000 men was ferried across the mouth of the Rusenski Lom River where it flows into the Danube. Exactly 60 Roman ships were used for this effort. Subsequently, the fortress was called Sexaginta Prista to celebrate the ensuing victory over the Dacians. It is possible that until then the fortress in question was known by the Thracian name of the Rusenski Lom River. Whatever the real origin of Sexaginta Prista’s name may be, the fact of the matter is that the name itself underscores the city’s importance for the Roman Navy because the “Port of the Sixty Ships" (today’s Bulgarian city of Ruse) is one of only two Roman frontier outposts on the Limes Moesiae, i.e. the Lower Danube frontier region, which have names connected with sailing. The other one is Colonia Ulpia Traiana Ratiaria whose name is derived from the Latin word “ratis" (raft) or from “ratiaria", a type of vessel.
Archaeological excavations conducted at Sexaginta Prista in 2005-2006 have demonstrated that the location of the original Roman military camp which existed between the 1st and the 3rd century AD remains unknown. There are hypotheses that it was built near the mouth of the Rusenski Lom River. The Roman archaeological finds on the hill of the fortress date to the 2nd-3rd century AD. The discovered structures include building remains from the canabae, a temple of god Apollo with votive tables of Apollo and the supreme Thracian deity, the so called Thracian Horseman also known as Heros, pottery, coins, and a sacrificial altar dedicated to Apollo, among others. The orientation and planning of the Apollo Temple reminds of a Christian temple. It is similar to pagan temples in the town of Ruchey, Southern Bulgaria; Benwel, England; and Porolisum in Dacia (today’s Romania). Its planning is construed as evidence that the early Christians modeled their churches on the Roman pagan temples. Apollo’s temple in Sexaginta Prista existed until the end of the 3rd century AD, and after that, possibly in connection with the adoption of Christianity, it was demolished, and a principium (the main building of the command staff of the Roman camp (castra)) was built in its stead, most probably during the reign of Roman Emperor Constantine I the Great (r. 306-337 AD). This is also when the Late Antiquity fortress walls of Sexaginta Prista (unearthed in 1976-1978) were erected. The principium was in use until the early 380s when the city was damaged by the barbarian invasions of the Goths, and again until the beginning of the 5th century. Out of a total of 204 coins discovered in Sexaginta Prista during the latest archaeological excavations in 2005-2006, about 100 date to the 4th century AD.
Archaeological finds of coins and pottery indicate that the hill of Sexaginta Prista was inhabited during the Late Antiquity and Early Byzantine period (5th-6th century AD), and during the First Bulgarian Empire in the 9th-11th century. Not unlike the rest of the Roman fortresses on the Limes Moesiae, the Roman city of Sexaginta Prista was overran by barbarian invasions several times, the last one being the invasions of Avars and Slavs at the end of the 6th century and the beginning of the 7th century AD, which put an end to the life of the city in the Early Byzantine period. In the 9th-10th century AD, during the First Bulgarian Empire (632/680-1018 AD), the Bulgarian settlement Ruse was built on the site of the Roman ruins of Sexaginta Prista. The discovery of a Christian grave and other human bones are taken to mean that in the 12th-14th century, i.e. during the Second Bulgarian Empire (1186-1396 AD), the hill was one of the necropolises of the medieval Bulgarian city of Ruse. The other archaeological finds on the hill of Sexaginta Prista are from the end of the Ottoman period, i.e. the 19th century.
The ruins of Sexaginta Prista are located in the northwestern part of today’s Bulgarian city of Ruse on a hill next to the Danube River. They were first designated by Austro-Hungarian geographer and archaeologist Felix Kanitz at the end of the 19th century based on the distances marked on Roman road maps. The first major archaeological excavations of Sexaginta Prista were conducted at the end of the 19th century by the Czech-Bulgarian bothers Karel and Hermann Skorpil, who are the founders of modern-day Bulgarian archaeology. Further rescue excavations were made in the first half of the 20th century during the construction of Ruse’s Military Club. Regular archaeological excavations were conducted in 1976-1978 and again in 2005-2006. The excavations have revealed a 50-meter section of Sexaginta Prista’s northwestern wall, a fortress tower, six Roman buildings, and a temple of Apollo. The excavations in 2006 discovered the ruins of the Roman military headquarters which was used from the first quarter of the 4th century AD until the 410s AD (it was dated based on the discovered coins and pottery). Since 2002, part of the ruins of the Ancient Roman city of Sexaginta Prista have been exhibited in situ as a cultural tourism site.
The principium (plural: principia) was the administrative and religious center, and was the most important building in any Roman fort. It was situated at the centre of the fort where the via praetoria and the via principalis crossed.