Disaster at Philippopolis
Rather than being downhearted by his failure at Nicopolis, Cniva and his army marched north, causing as much havoc and destruction as possible. While Decius pursued the enemy, he didn’t make inroads and elected to rest his army after an exhausting march. This was just the opportunity that Cniva was waiting for. He launched a surprise attack on the Romans and forced a disorganized retreat. The Roman army sustained significant losses while Decius and his generals had to flee with the remnants of their men. Cniva was able to gather the weapons and supplies left by the panicked enemy and continued marching, this time south, towards Philippopolis.
As the Romans were still in the process of regrouping, Cniva took the opportunity to lay siege to the city. Unlike the previous siege attempts, the barbarians were successful in capturing Philippopolis. The city was defended by a small Thracian army led by Titus Julius Priscus. The inhabitants of the city declared him as emperor to provide him with authority to make a deal with the enemy. Eventually, Priscus agreed to surrender if Cniva guaranteed the safety of the people. However, the Goths reneged on the agreement. As soon as the gates opened, Cniva and his men looted the city, massacred the inhabitants and burned it. There is no record of what happened to Priscus though it is likely that he was murdered.
Let Battle Commence
Decius finally reorganized his army and once again pursued the Goths. He was accompanied by his son, Herennius Etruscus, and Gallus. Herennius had been made co-emperor at the start of 251, but he didn’t live long enough to enjoy it. When Cniva heard that the Romans were in hot pursuit, he ended the retreat and positioned his army in a marshy part of a river valley close to the city of Abritus. It seems as if Cniva was familiar with the area and specifically chose it to lure the Romans into a trap.
There is a suggestion that Decius chose the battlefield because there was flat terrain which would have proved advantageous to the Romans. Decius had been a governor in Moesia Inferior so he would have known the terrain. However, he made a critical error by following the enemy to a site preferred by Cniva. The Gothic leader divided his forces into between three and seven units (the number varies according to the source). He placed his front line on the swamp’s far side and another unit behind it, Cniva chose to lead the rear unit. He also put other divisions on both sides of the battlefield, but they were obscured by his long front line.
Once Decius had heard that the Goths had paused, he wanted to mimic the enemy’s successful attack after the siege of Nicopolis. It was a terrible blunder because the moment he marched his army to the swampy terrain chosen by Cniva, he was playing into the hands of the enemy. To make matters worse, he organized his army in typical battle formation, a tactic anticipated by Cniva who had another trick up his sleeve.