The Battle of Manzikert was fought on August 26, 1071, during the Byzantine-Seljuk Wars (1048-1308).
Ascending to the throne in 1068, Romanos IV Diogenes worked to restore a decaying military situation on the Byzantine Empire's eastern borders. Passing needed reforms, he directed Manuel Comnenus to lead a campaign against the Seljuk Turks with the goal of regaining lost territory. While this initially proved successful, it ended in disaster when Manuel was defeated and captured. Despite this failure, Romanos was able to conclude a peace treaty with Seljuk leader Alp Arslan in 1069. This was largely due to Arslan's need for peace on his northern border so that he could campaign against the Fatimid Caliphate of Egypt.
In February 1071, Romanos sent envoys to Arslan with a request to renew the peace treaty of 1069. Agreeing, Arslan began moving his army into Fatimid Syria to besiege Aleppo. Part of an elaborate scheme, Romanos had hoped that the treaty renewal would lead Arslan away from the area allowing him to launch a campaign against the Seljuks in Armenia. Believing that the plan was working, Romanos assembled an army numbering between 40,000-70,000 outside Constantinople in March. This force included veteran Byzantine troops as well as Normans, Franks, Pechenegs, Armenians, Bulgarians, and variety of other mercenaries.
The Campaign Begins
Moving east, Romanos' army continued to grow but was plagued by the questionable loyalties of its officer corps including the co-regent, Andronikos Doukas. A rival of Romanos, Doukas was a key member of the powerful Doukid faction in Constantinople. Arriving at Theodosiopoulis in July, Romanos received reports that Arslan had abandoned the siege of Aleppo and was retreating east towards the Euphrates River. Though some of his commanders wished to halt and await Arslan's approach, Romanos pressed on towards Manzikert.
Believing that the enemy would approach from the south, Romanos split his army and directed Joseph Tarchaneiotes to take one wing in that direction to block the road from Khilat. Arriving at Manzikert, Romanos overwhelmed the Seljuk garrison and secured the town on August 23. Byzantine intelligence had been correct in reporting that Arslan had abandoned the siege of Aleppo but failed in noting his next destination. Eager to deal with the Byzantine incursion, Arslan moved north into Armenia. In the course of the march, his army shrank as the region offered little plunder.
The Armies Clash
Reaching Armenia in late August, Arslan began maneuvering towards the Byzantines. Spotting a large Seljuk force advancing from the south, Tarchaneiotes elected to retreat west and failed to inform Romanos of his actions. Unaware that nearly half his army had departed the area, Romanos located Arslan's army on August 24 when Byzantine troops under Nicephorus Bryennius clashed with the Seljuks. While these troops successfully fell back, a cavalry force led by Basilakes was crushed. Arriving on the field, Arslan dispatched a peace offer which was quickly rejected by the Byzantines.
On August 26, Romanos deployed his army for battle with himself commanding the center, Bryennius leading the left, and Theodore Alyates directing the right. The Byzantine reserves were placed to the rear under the leadership of Andronikos Doukas. Arslan, commanding from a nearby hill, directed his army to form a crescent moon-shaped line. Commencing a slow advance, the Byzantine flanks were struck by arrows from the wings of the Seljuk formation. As the Byzantines advanced, the center of the Seljuk line fell back with the flanks conducting hit and run attacks on Romanos' men.
Disaster for Romanos
Though capturing the Seljuk camp late in the day, Romanos had failed to bring Arslan's army to battle. As dusk neared, he ordered a withdrawal back towards their camp. Turning, the Byzantine army fell into confusion as the right wing failed to obey the order to fall back. As gaps in Romanos' line began to open, he was betrayed by Doukas who led the reserve off the field rather than forward to cover the army's retreat. Sensing an opportunity, Arslan began a series of heavy assaults on the Byzantine flanks and shattered Alyates' wing.
As the battle turned into a rout, Nicephorus Bryennius was able to lead his force to safety. Quickly surrounded, Romanos and the Byzantine center were unable to break out. Aided by the Varangian Guard, Romanos continued the fight until falling wounded. Captured, he was taken to Arslan who placed a boot on his throat and forced him to kiss the ground. With the Byzantine army shattered and in retreat, Arslan kept the defeated emperor as his guest for a week before allowing him to return to Constantinople.
While Seljuk losses at Manzikert are not known, recent scholarship estimates that the Byzantines lost around 8,000 killed. In the wake of the defeat, Arslan negotiated a peace with Romanos before permitting him to depart. This saw the transfer of Antioch, Edessa, Hierapolis, and Manzikert to the Seljuks as well as the initial payment of 1.5 million gold pieces and 360,000 gold pieces annually as a ransom for Romanos. Reaching the capital, Romanos found himself unable to rule and was deposed later that year after being defeated by the Doukas family. Blinded, he was exiled to Proti the following year. The defeat at Manzikert unleashed nearly a decade of internal strife which weakened the Byzantine Empire and saw the Seljuks make gains on the eastern border.