When you travel around Bulgaria in search of ancient Roman heritage, going deep into the region known as Ludogorie, or Deliorman (which translates as Mad Forest), may seem counterintuitive. The region, in the northeast, is known mainly for its rolling hills, industrial agriculture and generally drab towns.

Yet, near one of the larger cities, Razgrad, lie the remains of an ancient town that witnessed one of the most devastating events in Roman history.

In July 251, by the swamps at an all but forgotten corner in the Balkan realms of the Roman Empire two armies stood against each another. The legions of Emperor Decius (249-251) and his son and co-ruler, Herennius Etruscus, faced the army of the Goth leader, Cniva, in the final meeting of a long cat-and-mouse game.

A bronze helmet-mask from the 1st-2nd centuries

Several months previously, Cniva had crossed the Danube in the biggest Gothic incursion into the Balkans and wrecked havoc in the lands on both sides of the Stara Planina mountain range. Now, Cniva was trying to take his men and booty into safety north of the Danube.

But Decius had guessed Cniva's intentions, and was there, near the city of Abritus, in a bid to stop the Goths from withdrawing unpunished.

The manpower of the two armies were probably equal (estimates vary) but Decius had the confidence that he would defeat his enemy, as he had done earlier, at Nicopolis ad Istrum. Yet, Cniva strategically hid some of his regiments at a marshy part of the battlefield. When the Romans broke the Goths' lines and stormed deeper, they were besieged by the men in the marshes.

What followed was a massacre. The emperor, reportedly, had the misfortune to see his son and heir killed. His military discipline provided him with enough strength to brush the tragedy away, saying "Do not mourn, as the death of a soldier is not a great loss to the Republic." Soon, however, Decius was himself dead, in one of the most devastating defeats the Roman army had ever suffered. Neither his, nor his son's bodies were recovered from the mud.

The towers of Abritus came in a variety of shapes to impede wartime destruction

Abritus, the town near which the drama unfolded, is one of those Roman settlements that appeared in the region as military camps soon after the Roman conquest, and were later promoted to full-scale cities. It was founded sometime at the end of the 1st or the beginning of the 2nd centuries, either by Emperor Vespasian (69-79) or Emperor Trajan (98-117). The region is generally flat, and the camp was built on an easily defensible hill, which is now called Hisarlaka. The location was wisely chosen, as Abritus stood on the main road connecting Sexaginta Prista (modern Ruse) on the Danube with Mesembria (modern Nesebar) on the Black Sea and Hadrianopolis (modern Edirne). Two lesser roads leading to Nicopolis ad Istrum (near Veliko Tarnovo) and to Odessos (modern Varna) crossed in the vicinity.

By the early 3rd century, the camp and the civic settlement nearby had grown big enough to be promoted to the rank of a true city.

A bronze master mould of Hercules used by a local workshop to manufacture votive tablets. Abritus was a centre of production of cult object. Fourteen such matrixes were discovered in its vicinity, in 1922, shedding light not only on the local production, but also on its most popular deities. They included Zeus and Hera, Hercules, Artemis, and unidentified goddesses and god riders from the East

Ancient Abritus was created in the cookie-cutter shape of a standard Roman city. It had straight streets, a forum and an aqueduct, shrines and religious buildings for a number of deities. Some of them were local, like the Thracian God Rider, others were Graeco-Roman, like Zeus, Artemis and Apollo. There were also arrivals from the Middle East, like Sabazios, Cybele and Mithras, and from Central Europe, like Epona. The citizens also worshiped a local deity, the mysterious Goddess of Abritus. In the city, there were workshops dedicated solely to the production of votive tablets of metals. Their presence is now known by the number of bronze master moulds that are among the most interesting exhibits in the museum of Abritus Archaeological Reserve.

The citizens of Abritus were local Thracians as well as veterans from the Roman legions, settlers from Italy and Gaul, and Greeks from Asia Minor. In the early 4th century, these were joined by Goths who were settled in the city as foederati, or "Barbarian" allies of the Roman Empire.

Tombstone of a Roman couple

The city got its first proper fortification wall long after the fateful battle of 251. Constructed at the very beginning of the 4th century, the fortress was situated at the easily defensible height of Hisarlaka. It had 35 towers and four major gates, enclosing roughly an area of 15 hectares. A section of it is well preserved. It boasts an interesting variety of towers – rectangular, U- and fan-shaped – that modern archaeologists have named the Abritus system. The unusual shape of the towers was for a purpose: during a siege, it was harder to hit with a catapult a target that had bent walls. Still, the walls proved useless in 376, when the Visigoths raided Abritus and burnt it to the ground.

The city remained a major regional centre in the 5th-6th centuries, but danger was never afar. In 447, for example, the Huns of Attila conquered and pillaged it. The fortifications were restored a century later, under Emperor Justinian (527-565), along with dozens of other fortresses in his Balkan realms. Soon, however, the pressure from the so-called Barbarians was too much for the citizens of Abritus. After a devastating pillage from the Avars, probably in 586, the city was abandoned and soon its name was all but forgotten.

The remains of Abritus attracted archaeologists in the 1880s, when an early-Christian basilica on the Hisarlaka hill was excavated and – wrongly – interpreted as a temple to Apollo. Systematic digs began in 1953, but sadly a lot of the remains are now under a pharmaceutical factory.

Through the decades since the beginning of the excavations, the complete course of the fortification wall was discovered, together with a number of private and public buildings, stone reliefs and artefacts.

In 1971, the biggest treasure of late Roman gold coins ever in Bulgaria were discovered by the fortified walls. The find consisted of 835 gold coins, weighed about 4 kg and dated back to the 5th century. According to a hypothesis, it was hidden in 487, when the Goth foederati living around Novae (modern Svishtov), on the Danube, rebelled. Apparently, someone in Abritus decided to take preventive measures against the impending pillage. The danger never materialised: led by Theodoric the Great, in 488, the Goths headed west to Italy, where they established a kingdom. For some reason, the money of the Abritus hoard remained in their hiding place.