Battle of the Dvina River

The Battle of the Dvina River, also known as the Battle of Black Waters, was the final and most pivotal engagement of the Third War of the Confederation. A united Karelian-Sartvelian army defeated the Obotrite host in an engagement that initially looked to be a victory for the tribes, as Niklas II Saarelainen, the Grand Duke of Karelia, was killed amidst the combat. The day was saved by his nephew and successor, Duke Niklas of Viipuri, who managed to successfully rally the Karelian infantry and hold long enough for the Sartvelian cavalry to secure a victory.

The battle ended the threat posed by the Obotrites to Karelia and Sartvelia, and resulted in their ultimate annexation the next year, along with the Expulsion of the Magyar further south. It provided a major source of popularity for the now-Grand Duke Niklas III Karjalainen, who would go on to achieve another major victory at the Battle of Satala the next year.

Background
By 747, the Third War of the Confederation had been an incredibly back-and-forth conflict. The Obotrites, led by the Magyar chieftain Bulscu Harka, had achieved a decisive victory against the Karelians and Sartvelians at the Battle of Rereg in 745, unleashing the army in a mass looting spree across Livonia. They successfully besieged and took Aizrakule Castle in an assault, but were unable to take the port city of Turaida due to the intervention of the Karelians' superior navy. The Obotrites continued to keep the Sartvelians at bay through the taking of the fortress Didgor in September.

Meanwhile, Grand Duke Niklas II Saarelainen was distracted by his ongoing conquest of Serkland, and was unable to provide any effective support to fight the Obotrites. In fact, he seemed to be actively trying to pull support away from them, openly complaining about the perceived weakness of the mainlanders. While the victory at the Battle of Mildenitz provided a small morale boost in Karelia and Livonia, it did not permit any organisation of a major counterattack.

The Obotrites viewed this inner turmoil as the perfect opportunity to invade Karelia Proper, something previously believed to be unthinkable. The Slavs and the Magyar crossed the Dvina River into Karelia in March of 746, and began to loot the countryside, reaching within just a few miles of Viipuri. This offensive was not nearly as successful as in Livonia, as many Karelians began to join with nobles in order to wage guerrilla-style attacks against the Obotrites. Several skirmishes left many dead on both sides, as the Karelians were unwilling to move any major force out, afraid to leave Viipuri defenceless.

In late September, Niklas II Saarelainen achieved a decisive victory against the Serks at the Battle of Dere, effectively pacifying the eastern half of the Shahdom. He then finally decided to intervene in the war to the south, and gathered his army, bolstered by experienced Tatar and Cuman mercenaries. They arrived in Karelia in November, unable to do much campaigning due to the winter. A victory was achieved in a skirmish near the village of Mikkeli in January, and the Grand Duke was able to secure the support of a Sartvelian force, who received passage through the territory of Nova Ukrayina in order to evade the Obotrites.

The Obotrites withdrew from Karelia in February, taking a position just south of the Dvina. A stalemate was held as the Grand Duke awaited the support of the Sartvelians, who arrived on the afternoon of March 10. The arrival of the Sartvelian detachment greatly worried the Obotrite leadership. Chief Krytoi of the Wends urged caution and suggested a withdrawal, but Mstivoj of the Skalvians, eager to make up for his loss at Mildenitz, and Bulscu Harka of the Magyar both agreed they had little choice but to stay and fight. A retreat would mean allowing the Karelians to consolidate, retake Livonia, and push into Obotrite lands. It would also lead to a decrease in morale, which, after the Natangians had left the confederacy, was something the Obotrites could not afford. Krytoi was convinced and it was decided that they would try their fortunes in battle.

Karelians
The Karelian army was not at full strength at the outset of the battle. Losses taken by Karelian and Livonian troops during the war withered down their numbers. This was exacerbated by the desire of many nobles to garrison Viipuri in the event the Obotrites achieved another victory. These nobles included Vetseke III of Livonia. Furthermore, most of the available troops from the island duchies were unavailable due to the occupation of Serkland. With all of these factors, the Karelian army was still able to field over 5,000 men.

The Karelian cavalry almost entirely consisted of a force of 700 experienced Tatar and Cuman cavalry mercenaries, who had previously served with Niklas II in Serkland. They were supplemented by some savanorat. The infantry was the largest contingent, mostly consisting of nobles and huskarls from Karelia and the islands. Levy infantry from Stedingen also participated in the battle, along with some militia from Saaremaa and Hiiumaa.

Sartvelians
The Sartvelian contingent of a little over 1600 men was led by Germain Eristavi, a cousin of King David. The force was somewhat evenly divided between cavalry and infantry, the latter being largely composed of pikemen, swordsmen, and archers. The force had previously marched a long distance to join with the Karelian army, and many of the infantry were tired out, and, as a result of the Obotrites' opening moves, did not receive proper rest.

Obotrites
The Obotrite army was the standard blend of varying tribal warriors typical of previous armies. Similar to their Karelian opponents, they were not operating at full strength either. One of the tribes, the Natangians, pulled out of the confederacy and had its 1,000 man contingent return to their lands. A sizeable force was also sent to raid around Turaida, as the Obotrite commanders feared that Karelian reinforcements could march up from Livonia if they were not distracted. Despite these setbacks, the Obotrites were still able to field an impressive force of over 8,000 men.

2,000 Magyar cavalry formed the core of the army, including the celebrated huzars. The bulk of the army was composed of light infantrymen fighting in varied styles, depending on the tribe of origin. These included Karelian-style axemen, javeliniers, slingers, and even pikemen, copied from the Sartvelians. The Skalvians were able to field an additional cavalry force of around 100 noblemen but were nowhere near the skill of the Magyar.

The Battle
Just before dawn on March 11, the Obotrites moved their centre infantry forces at Valdi Bridge and repositioned them on their right flank, facing Niklas II's forces. They were able to accomplish this under cover of the night and then proceeded to set the wooden bridge on fire. This alerted Karelian forces, who were quickly ordered by Niklas of Viipuri to reposition themselves. The advantage the Obotrites hoped to gain here was negligible, due to the speed of the Karelian mounted infantry in equipping themselves and moving.

Chief Krytoi led the first assault across the river, sending Magyar cavalry against the Sartvelians on their left flank, followed up by infantry. The Sartvelians were able to organise and hold, bolstered by the eventual arrival of Karelian infantry from Niklas of Viipuri's detachment. Heavy fighting would continue in the river crossing at this point throughout the day, with both sides falling back and re-engaging several times.

On the opposite river crossing, Obotrite forces crossed and engaged Karelian forces. This lasted only a few minutes as the Duke of Viipuri's forces arrived to force them back. Bulscu Harka was personally leading the attack and had expected a called a withdrawal. The Obotrites retreated back across the river, closely followed by the Karelians. Bulscu Harka's cavalry fell back slightly to the east, while Mstivoj withdrew his infantry more to the west, towards a nearby hill. Along the way, he placed a small ambush of slingers and javeliniers in a forest near the river.

Niklas II and his cavalry personally pursued Bulscu Harka to about a mile and a half away from the river, before the Magyars turned against the Karelians. The Grand Duke