The Fourth Battle of Marnus Pell was the first engagement following the nine-year stalemate during the Tevinter Civil War, in -622 Ancient. Imperial troops enveloped Qarinus League forces in and around Marnus Pell, killing or capturing many of them, and forcing the rest to flee. It resulted in the collapse of the front line for the League and a complete withdrawal from Marnus Pell back to Vyrantium in the southeast, undoing all of the gains made in the League offensive several years ago.
The Tevinter Civil War had raged for almost twenty years by -622 Ancient, with both sides becoming exhausted and having a nine-year stalemate from -631 until -622. The Qarinus League, the alliance of Altus magisters opposing House Calphayus' claim to the Imperial throne, had been stopped after a long offensive at the Second Battle of Asariel and forced back towards the port city of Marnus Pell, further south. The front-line remained there during the stalemate, running from Marnus Pell in the northwest down to Vol Dorma in the southeast. The League's defensive positions were heavily fortified during the stalemate.
By -622 Ancient, Archon Justinian of House Calphayus had replenished the Imperial Army and was ready to begin an offensive along the front. But, due to the League forces being numerically superior around Marnus Pell and being firmly entrenched, the Archon came up with a more grandiose plan for eliminating the League garrison there. While General Glabrio Regulus, the commander in the city, had Marnus Pell and the nearest stretch of the defensive line prepared for an assault, the other half, ending ad Vol Dorma, was not as strongly protected. It became part of a plan to envelop the entire League garrison in the area.
The 1st Army (consisting of 55,000 men), under General Augustus Ursinian, launched a series of small attacks along the front line, especially around Marnus Pell, to give the appearance that Justinian had opted for a frontal assault. The League forces had little trouble repelling the feint attacks. Ursinian kept the bulk of his force back until he got the message to strike, when General Constantine Raltus' 2nd Army, also having 55,000 men, had gotten into position to surround the city and nearby positions from the south. He did intensify the attacks to make it look like they were really trying, but did his best to keep as many of his troops from dying in the first couple days of battle. At the same time, the 2nd Army under General Raltus went south.
Fall of Vol Dorma
As the fighting grew more intense in the north, Raltus attacked the town of Vol Dorma and the surrounding positions. The garrison there, about 25,000 strong, were taken completely by surprise and overwhelmed, with most of the local residents welcoming Imperial troops as liberators. The League loyalists did put up fierce resistance in the keep of Vol Dorma and the central district, after the shock wore off, but they were ultimately defeated.
Many of the League soldiers surrendered and defected to the Imperial Army, while more simply deserted their positions and melted into the countryside, selling their armor and weapons for civilian clothes. In total, only about 4,000 stragglers made it to Marnus Pell, but by the time they arrived it was far too late.
On the fourth day since the beginning of the offensive, the 2nd Army had secured the southern sectors of the front and quickly moved north, before any stragglers could bring word of what happened to General Regulus. The result was the League forces being attacked from the rear as the 2nd Army moved northwards along their defensive line, causing confusion and panic. Once Ursinian received word that Raltus had begun his attack, he ordered the rest of his troops into battle. Attacked from the front and the rear, the League forces around and on the line south of Marnus Pell (numbering about 125,000) were forced back towards the city.
After two days of fighting, Regulus gave permission for his forces to attempt a break-out while Imperial lines were thin. It was his last order, since he was killed leading a regiment personally into battle against Imperial forces a day later. However, once that command was given, the League troops still holding their positions lost the will to fight and began to retreat in droves, causing a collapse of the front. The fighting became even more intense as the League soldiers fled, and a significant amount of them actually made it out of the encirclement. Most of the troops that could not escape stopped fighting on the sixth day and surrendered, but a few pockets of resistance continued to fight for the next few days.
The operation resulted in the total collapse of the front line. League troops were forced to withdraw to Vyrantium, in the southeast, losing all of the gains they made in the last offensive, which took place nine years ago. Out of the total 150,000 men stationed on the front line, only about 45,000 managed to reach Vyrantium. The rest were either killed, captured, or had deserted. Among the casualties was the general commanding the army at Marnus Pell, Glabrio Regulus. The Imperials lost about 40,000 men in total. The battle also increased Justinian's reputation as a strategist and tactician at home and abroad, putting shock and confusion into the Altus magisters leading the League, such as Maximilian Styrak and Jozef Tyrans.
Later, Imperial historians would consider the engagement to have been the "beginning of the end" for the Qarinus League, as the tide had been turned against it permanently, and it never recovered from the losses that were taken in that battle. The battle also demoralized the soldiers and officers of the Qarinus League's Allied Forces, and opened the road to Vyrantium for Justinian's Imperial Government.