Christendom had been ripped in half, and Byzantium was now dangerously and terrifyingly alone. From now on, the powers to its west would offer no succor, and the empire would have to face the enemies to its east with only its own diminishing resources.
The weakened empire still had its army, but it was no longer the peerless fighting force that had made it the superpower of the Mediterranean. Years of neglect since Basil II’s death had reduced it to virtual impotence, and the court, terrified of a military uprising, did its best to weaken it further—even taking the insane step of disbanding the local militias that guarded the frontiers. Outwardly, the empire may have looked glorious, but on the inside it was rotten and hollow, waiting for an enemy to break the brittle shell. Trapped in the firm grip of squabbling aristocrats, the throne was unlikely to produce a figure capable of undoing the damage, and Byzantium was given no chance to recover its strength.
While the empire was still reeling from its struggle with the papacy, a new and devastating enemy made its military weakness all too apparent. The Seljuk Turks had already taken the Muslim world by surprise. Originally a central Asian nomadic tribe, they spread over Iran and Iraq, managing to seize Baghdad in 1055, replacing the weak and crumbling Abbasid caliphate. After crossing the undefended Byzantine frontiers, by 1067 they were looting their way through Armenia virtually unopposed. Combining the hunger of nomads in search of plunder and pastureland with the predatory aggression of jihadists, the Seljuks were unlike anything the Byzantines had seen before. Their mounted raiders struck fast and without warning, making it difficult to know where to concentrate the defenses. The unwieldy empire was used to dealing with states and armies, not roving bands slashing across their borders. In any case, the humiliated, demoralized imperial army could no longer offer much resistance.
Emperor Romanus Diogenes was a determined if not a gifted general, and when the Seljuks crossed the border in strength during his reign, he somehow managed to push them back across the Euphrates. Unfortunately for the empire, the small victory awakened all the aristocratic courtiers’ old fears that a strong emperor would restrict their privileges. By the time the Turks returned the next year and seized a small Armenian fortress in the town of Manzikert, support for the emperor had begun to dangerously erode.
Oblivious to the mounting dissension, Romanus marched out with his army, determined to evict the Turks from Christian lands once and for all. On August 26, 1071, the two armies met, and the most fateful battle in Byzantine history began. Despite massive defections from his unreliable mercenaries, the emperor managed to push the Turks back, but at a critical moment his scheming nobles betrayed him and withdrew. The cream of the army was slaughtered on the spot, and Romanus Diogenes was captured and forced to kiss the ground while the sultan, Alp Arslan, rested a boot on his neck.
The humiliation of an emperor groveling in the dust seemed to many later Byzantines as the awful moment when everything started to go wrong, but if it marked the beginning of their final decline, then it was the Byzantines themselves who were to blame. The battle could easily have been avoided. At Manzikert, the sultan had tried to come to terms, but the petty nobles had refused his offers and insisted on being the authors of their own destruction. And while the loss of prestige and manpower after the battle were bad enough, they could have been recovered from. It was the behavior of the aristocrats afterward that truly wrecked Byzantium. After fleeing from the scene of their defeat, the nobility escaped to spread chaos throughout the empire, unleashing civil war in their vain attempts to seize control of the sinking Byzantine ship. Rival claimants to the throne rose up in a bewildering succession and were overthrown just as quickly by yet another general with imperial dreams.