After the deaths of Zoe and Theodora, Byzantium was in bad shape. From a strong position during the rule of Basil, bad management had reduced the wealth and defences of the Empire, leaving it open to invasion. There being no heir to the throne, the rule of Byzantium was once again up for grabs, leading to a succession of weak emperors: Michael Bringas, Isaac Komnenos and Constantine Doukas.
In 1064, on the death of Constantine Doukas, his son Michael Doukas, aged 17, and his nephews Constantios and Andronikos Doukas were still children. They were each officially given the title of emperor, but it was understood that someone else would have to rule the Empire. Their mother, the Empress Eudokia, acted as regent.
Romanos Diogenes was a general in the army who rose to prominence. Eudokia decided he would be a good choice to lead the Empire out of its troubles, so in 1068 she married him and he was appointed as Emperor of Byzantium. This made him a lot of enemies in the Doukas family, who naturally wanted to see their boys in charge.
A nomadic Turkish people called the Seljuks arrived on the scene at about this time. They came from Mongolia, and had first been noticed by the western world when they conquered Transoxania (modern Uzbekistan) in about 950. They converted to the Sunni Muslim religion of the area. By 1055, they had taken Baghdad and were intent on expanding towards the southwest, ultimately to conquer their sworn enemies, the Shi'ite Muslims of Egypt. They had no real interest in Byzantium, but took those Byzantine lands that were on their route to Egypt. By the time of Romanos, they had conquered the eastern part of Anatolia, as far as Caesaria (modern Kayseri). Their leader was a man called Alp Arslan.
Romanos Takes Control
The previous Byzantine emperors had left the army in a poor state, badly paid, with many foreign mercenaries. Romanos spent a couple of years building it up again. Then in March 1071 he started his campaign to retrieve eastern Anatolia from the Seljuks. He set out with a force of about 70,000 men and met with no real opposition until he reached Lake Van in what is now eastern Turkey. Here he split his force, sending more than half to camp by Lake Van under the command of experienced general John Tarchaniotes, while he led a smaller force about 30 miles north to take the small fortress of Manzikert (modern Malazgirt), which he did without any problems.
Now a strange development took place. The Turkish Sultan, Alp Arslan, arrived at Lake Van and Tarchaniotes's army retreated and disappeared, sending no word to Romanos. It's not clear whether there was a battle, or whether there was treachery involved, but the upshot was that Romanos now had less than half his full force.
The Battle of Manzikert
The following day, a troop of Seljuk bowmen started harassing the fortress of Manzikert, injuring some of the senior officers.
The day after, a delegation arrived from Alp Arslan offering a truce - he wasn't interested in conquering Byzantium and really wanted to concentrate on Egypt. Romanos refused any compromise - he must have been very conscious of the fact that the Doukas family back in Constantinople were just waiting for him to slip up so that they could promote their own candidates to the throne. And even with half his army, he should still have had enough to take on the Seljuks, who preferred raiding to standing battles.
Romanos prepared his troops for battle with himself in the centre, a general called Bryennius taking the left flank and another called Alyattes taking the right. Guarding the rear was none other than Andronikos Doukas, potential candidate for the throne himself. The army marched eastward against the enemy, but the Seljuks continually withdrew, forming a huge crescent around the Byzantines. This went on all day until he realised that the sun was about to set soon. Romanos gave the order to turn and withdraw.
At that moment, the Seljuks attacked. It was a rout. Andronikos in the rearguard spread the word that the battle had already been lost and his troops fled. The Seljuks closed in from all sides while many of the Byzantine-paid mercenaries fled if they could. Romanos and the loyal Byzantines fought on, but most were killed. Eventually a small group of survivors, including Romanos himself, were taken captive and the battle was over.
The Emperor in Chains
The following morning, Romanos was led in chains to Alp Arslan, who could not believe that this was the Emperor of Byzantium. Eventually persuaded by both Turks and Byzantines that he was indeed who he said he was, the Sultan ordered Romanos to acknowledge his defeat by placing his head under the Sultan's foot. Then he treated him as an honoured guest, sharing meals together and talking.
The Sultan and the Emperor came to a peaceful settlement - the Seljuks would be allowed to keep the lands they had already conquered but would go no further towards Byzantium; they were, after all, on their way to Egypt. In addition, the Byzantines would pay a lump sum of 1.5 million gold pieces, and an annual tribute of 360,000, and one of Romanos's daughters would marry Alp Arslan's son.
Meanwhile back in Byzantium, bad news was arriving into the city. Not only did confused reports come in from Manzikert of the disaster and the capture of the emperor, but reports came in from the west that the Normans had finally captured Bari, the last Byzantine land in Italy. Romanos was held to be directly responsible for both events and the Doukas family saw this as their chance to seize control. John Doukas, brother of the previous emperor, Constantine, had Eudokia arrested and sent into exile; Michael Doukas, son of Constantine, was declared emperor and was crowned in Hagia Sophia. And Andronikos Doukas, whose treachery was at least partly responsible for the disaster at Manzikert, was instructed to capture the deposed Romanos and bring him back to Constantinople.
Romanos gathered what was left of his army and tried to fight his way back to the capital, but after two defeats he realised his time was up; he surrendered. Back in Byzantium, his eyes were brutally gouged out and he died of his wounds a few days later.
Romanos had made a peace treaty with the Turks which would have protected Anatolia, although with the loss of the lands to the east. The new emperor, Michael, refused to respect this treaty and wouldn't pay any of the promised gold to the Turks. The Seljuks therefore saw the peace treaty as null and void, and continued their incursion into Anatolia. The Byzantines were powerless to stop them. By 1080, Alp Arslan's son controlled 30,000 square miles of central Anatolia, which he named the Sultanate of Rum, his method of pronouncing Rome. The heart of the Empire had been cut out, and with it the main supply of food to the Queen of Cities.
The Byzantine Empire was rapidly losing ground. Now it was reduced to western Anatolia and the Balkan peninsula. But even at this stage, a good, strong emperor could have revived the Empire. Michael Doukas was not such an emperor. And barely a century later, the Empire had to contend with the worst loss of all: the capture and sack of Constantinople itself.