In the meanwhile Michael ruled the Roman Empire together with his brother Constantine.. Their rule was disastrous for the Greeks for they neglected warlike matters, preferring always to lead a life of idleness.  They were made prisoners by the deceitful charms of self-indulgence and a shameful laziness disgraced them. At this time the Christian people who inhabited the delightful lands of the Roman Empire fled in terror from the Turks who came from the east.  A large number died under the swords of the evil Turks, all the cities were taken and the conquered people served and paid tribute to them. These cowardly rulers sent no troops out against them, and in consequence, by the decree of the Senate, their mother was married off to a distinguished warrior,  Romanus, [although] she, Eudocia, loved him rather for his courage than for his birth. He was called Diogenes because he had a forked beard.
On undertaking the government he left leisure to his stepsons and concerned himself with warlike matters, setting out to do battle with the Persians  who were raiding the unfortunate Greeks. The fortunes of this war varied; often he was the victor and put the Persians to flight, but the battles were frequently indecisive. Finally he sent out innumerable counts to defend the towns that had surrendered to him as a result of the reputation for valour  which he had everywhere acquired. He himself remained in camp with a small number of his best troops. Suddenly a huge force of Persians, led by their king, surrounded him and attempted to break into the camp. In their efforts to seize this they launched some massive assaults. The first and second of these were repulsed.  Eventually Romanus became anxious, realising that the camp was indefensible, and sensibly took steps, not for his own safety, but to save the lives of his men, whom he  saw to be gravely weakened both by the battle and by hunger. He ordered whatever money there was, and all the precious vestments and gold or silver ornaments to be scattered about the camp  so that if the Turks should manage to force their way in they might, on seeing these, break off the pursuit of the Greeks. The valuables were collected by the servants who had fled from the fighting - then the Greeks were forced to pass an unhappy and sleepless night. At dawn the huge Persian army came and surrounded the camp.  Spears flew from all sides and a host of arrows filled the air. The Greeks were unable to resist, and the Turks broke down the defences and forced their way in. But more intent on plunder than cutting down the [enemy] soldiers the Persians allowed many of them to escape.
 The lord of the Greeks was recognisable by the golden eagle which was fixed to his hauberk and shone more than other armour. He defended himself unceasingly, striking down the enemy spears with his sword. A flying arrow wounded an unprotected limb  and so he was finally captured, as were some of his men. After plundering the Romans’ camp the Persians led him to their own camp and gave him the seat of honour, next to their king. The latter asked him what would have happened if he had been Romanus’ prisoner.  The latter replied that, ‘If you had been at my mercy or that of my men I would have ordered you to be beheaded or hanged from a gallows’. The other said that he would never commit such an evil deed, but rather he wished henceforth to establish the lasting peace  that his ambassadors had already often requested, and that he would give his daughter to be baptised and married to the emperor’s son to ensure that the peace was more secure. They concluded a treaty with these conditions, and then the ruler of the Persians sent Romanus home loaded with gifts, and set all the men who had been captured free.  He honourably accompanied them for some distance and then gave the emperor permission to depart.
 Michael VII Ducas or Parapinakes, was the eldest son of Constantine X Ducas and Eudocia Macrembolitissa. After a joint reign as Byzantine emperor with his brothers Andronicus and Constantine (sometimes numbered XI, but not to be confused with the actual Constantine XI) from 1067 to 1071, joined by the usurper Romanus IV in 1068, he was made sole emperor in 1071 through his uncle John Ducas after the defeat of Romanus IV by Alp Arslan. The feebleness of Michael, whose chief interest lay in trifling academic pursuits, and the avarice of his ministers, was disastrous to the empire. As the result of anarchy in the army, the Byzantines lost Bari, their last possession in Italy, to the Normans in 1071, and were forced to cede a large strip of Asia Minor which they were unable to defend against the Seljuk Turks (1074).
 Constantine X Ducas left three children: Constantine, Andronius and Michael. His lack of interest resulted in Eudocia, their mother playing a major role in their upbringing. During the 1060s, the Seljuk sultan Alp Arslan allowed his Turkish allies to migrate towards Armenia and Asia Minor, where they sacked cities and plundered farmland. In 1064, they destroyed the Armenian capital at Ani. Contemporaries and later historians such as Michel Attaliate held the emperors responsible for this state of affairs.
 The senate and the Patriarch considered the gravity of the cituation and married Eudocia to the general Romanus Diogenes, a Cappadocian aristocrat who was young, brave and attractive on 1st January 1068.
 Romanus fought campaigns against the Turks in 1068, 1069 and 1070. In 1068, Romanus IV led an expedition against them, but his slow-moving infantry could not catch the speedy Turkish cavalry, although he was able to capture the city of Hierapolis. In 1070, Romanus led an expedition towards Manzikert, a city in eastern Turkey‘s province of Muş, now known as Malazgirt, a Byzantine fortress that had been captured by the Seljuks. He offered a treaty with Arslan: Romanus would give back Hierapolis if Arslan gave up the siege of Edessa. Romanus threatened war if Arslan did not comply, and prepared his troops anyway, expecting the sultan to decline his offer, which he did.
 Accompanying Romanus was Andronicus Ducas, an odd choice as Ducas was an old enemy of the emperor. Romanus left his best general, Nicephorus Botaniates, at home, suspecting his loyalties (although he was certainly more loyal than Ducas). The army consisted of about 5000 Byzantine troops from the western provinces, and probably about the same number from the eastern provinces; 500 French mercenaries under Roussel de Bailleul; some Turkish, Bulgarian, and Pecheneg mercenaries; infantry under the duke of Antioch; a contingent of Armenian troops; and some (but not all) of the Varangian Guard. Turkish sources give the number of troops to be closer to 200,000. Other sources estimate them to be around 40,000. The march across Asia Minor was long and difficult, the Byzantine population also suffered some plundering by Romanus’ German mercenaries, whom he was forced to dismiss. The expedition first rested at Sebasteia on the Halys, and reached Theodosopolis in June 1071. There, some of his generals suggested continuing the march into Seljuk territory and catching Arslan before he was ready. Some of the other generals, including Nicephorus Bryennius, suggested they wait there and fortify their position. Eventually, it was decided to continue the march. Thinking that Alp Arslan was either further away or not coming at all, Romanus marched towards Lake Van expecting to retake Manzikert rather quickly, as well as the nearby fortress of Khliat if possible. However, Arslan was actually in Armenia, with 30 000 cavalry from Aleppo, Mosul, and his other allies. Arslan’s spies knew exactly where Romanus was, while Romanus was completely unaware of his opponent’s movements. Romanus ordered his general John Tarchaneiotes to take some of the Byzantine troops and Varangians and accompany the Pechenegs and French to Khliat, while Romanus and the rest of the army marched to Manzikert. This probably split the forces in half, about 20,000 men each. Although it is unknown precisely what happened to Tarchaneiotes and his half of the army after this, they apparently caught sight of the Seljuks and fled, as they later appeared at Melitene and did not take part in the battle.
 William of Apulia is the only source for this stratagem.
 Romanus was unaware of the loss of Tarchaneiotes and continued to Manzikert, which he easily captured on August 23rd. The next day, some foraging parties under Bryennius discovered the Seljuk force and were forced to retreat back to Manzikert. The Armenian general Basilaces was sent out with some cavalry, as Romanus did not believe this was Arslan’s full army; the cavalry was destroyed and Basilaces taken prisoner. Romanus drew up his troops into formation and sent the left wing out under Bryennius, who was almost surrounded by the quickly approaching Turks and was forced to retreat once more. The Turks hid among the nearby hills for the night, making it nearly impossible for Romanus to send a counterattack. On August 25th, some of Romanus’ Turkish mercenaries came into contact with their Seljuk relatives and deserted. Romanus then rejected a Seljuk embassy and attempted to recall Tarchaneiotes, who was of course no longer in the area. There were no engagements that day, but on August 26th, the Byzantine army gathered itself into a proper battle formation and began to march on the Turkish positions, with the left wing under Bryennius, the right wing under Theodore Alyates, and the centre under the emperor. Andronicus Ducas led the reserve forces in the rear. The Seljuks were organised into a crescent formation about four kilometres away, with Arslan observing events from a safe distance. Seljuk archers attacked the Byzantines as they drew closer; the centre of their crescent continually moved backwards while the wings moved to surround the Byzantine troops. The Byzantines held off the arrow attacks and captured Arslan’s camp by the end of the afternoon. However, the right and left wings, where the arrows did most of their damage, almost broke up when individual units tried to force the Seljuks into a pitched battle; the Seljuk cavalry simply fled when challenged. With the Seljuks avoiding battle, Romanus was forced to order a withdrawal by the time night fell. However, the right wing misunderstood the order, and Ducas, as an enemy of Romanus, deliberately ignored the emperor and marched back to the camp outside Manzikert, rather than covering the emperor’s retreat. Now that the Byzantines were thoroughly confused, the Seljuks seized the opportunity and attacked. The Byzantine right wing was routed; the left under Bryennius held out a little longer but was also soon routed. Romanus was wounded and taken prisoner when the Seljuks discovered him.
 Three sons of Romanus are known: Constantine, from his first marriage died in 1073 and Leo and Nicephorus were sons from his marriage to Eudocia. None of the Greek chroniclers speak of a matrimonial alliance. There may be good reasons for this since Nicephorus led a rebellion against Alexius Comnenus in 1093 or 1094 and in 1095 an imposter claiming to be Constantine, the son of Diogenes led a rebellion with the Coumans. Ten years later, when Bohemond visited France, he was accompanied by a pretender who claimed to be the son of Diogenes: in Orderic Vitalis, book xii but not mentioned in the Vita Ludovici Grossi, chapter ix.
 The treaty consisted of the freeing of prisoners, the payment of tribute, an alliance and the ceding of Manzikert, Edessa, Manbig and Antioch to the sultan.
 Manzikert came to be seen as a disaster for the Empire; later sources greatly exaggerate the numbers of troops and the numbers of casualties. Byzantine historians often looked back and lament the ‘disaster’ of that day, pinpointing it as the moment the decline of the Empire began. It was not, however, an immediate disaster; most units survived intact and were fighting in the Balkans or elsewhere in Asia Minor within a few months. On the other hand, the defeat showed the Seljuks that the Byzantines were not invincible. Nevertheless, in hindsight historians are practically unanimous in dating the decline of Byzantine fortunes to this battle. It is also considered one of the root causes for the later Crusades: the West saw Manzikert as a signal that Byzantium was no longer capable of being the protector of Eastern Christianity.