The Double Disasters

Learning Objective

  • Identify the Double Disasters and their consequences

Key Points

  • A number of wars between the Normans and the Byzantine Empire were fought from c. 1040 until 1185.
  • In 1071, the Byzantines were defeated by the Normans during their conquest of Italy, thereby driving the Byzantines from southern Italy.
  • Even more dangerous than the Normans was a new enemy from the steppe: the Turks.
  • The Battle of Manzikert was fought between the Byzantine Empire and the Seljuq Turks on August 26, 1071, and proved a decisive defeat of the Byzantine army.
  • This defeat and the capture of the emperor Romanos IV Diogenes played an important role in undermining Byzantine authority in Anatolia and Armenia, the heartland of the Byzantine Empire.


Battle of Manzikert

A major battle between the Byzantines and the Turks that ended in a Byzantine defeat and ushered in the decline of the Byzantine Empire.


The people who in the 10th and 11th centuries gave their name to Normandy, a region in France. They were descended from Norse raiders and pirates from Denmark, Iceland, and Norway who, under their leader Rollo, agreed to swear fealty to King Charles III of West Francia.

The Normans and the Defeat at Bari

A number of wars between the Normans and the Byzantine Empire were fought from 1040 until 1185, when the last Norman invasion of Byzantine territory was defeated. At the end of the conflict, neither the Normans nor the Byzantines could boast much power. A Byzantine defeat in 1071 proved decisive for the disintegration and collapse of the empire.

The Normans had come from the Duchy of Normandy in West Francia, which in 911 had been granted to the Viking Rollo in the Treaty of Saint-Clair-sur-Epte by the French king Charles the Simple. The Normans and their new land took the name of these “Northmen.” During the time that the Normans had conquered southern Italy, and the Byzantine Empire was in a state of internal decay; the administration of the empire had been wrecked, and the efficient government institutions that provided Basil II with a quarter of a million troops and adequate resources by taxation had collapsed within a period of three decades. Attempts by Isaac I Komnenos and Romanos IV Diogenes to reverse the situation proved unfruitful. The premature death of the former, and the overthrow of the latter, led to further collapse as the Normans consolidated their conquest of Sicily and Italy.

Reggio Calabria, the capital of the tagma of Calabria, was captured by Robert Guiscard in 1060. At the time, the Byzantines held a few coastal towns in Apulia, including the capital of the catepanate of Italy, Bari. Otranto was besieged and fell in October 1068; in the same year, the Normans besieged Bari itself, and, after defeating the Byzantines in a series of battles in Apulia, and after any attempt of relief had failed, the city surrendered in April 1071, ending the Byzantine presence in southern Italy.

The Norman adventurer Robert Guiscard allied with the pope to drive the remaining Byzantines from southern Italy and replace them with a Roman Catholic Norman Kingdom. Guiscard was incredibly successful, and he turned his eye to conquering the entire Byzantine Empire. He crossed over into Greece, pillaged the countryside, and defeated the Byzantine army at the Battle of Dyrrhachium in 1081 CE. He died before he could complete his conquests, but southern Italy would never again be ruled by the Byzantine Empire.

The Turks and the Defeat at Manzikert

Even more dangerous than the Normans was a new enemy from the steppe, the Turks. These former pastoral nomads converted to Islam and ushered in a new phase of Islamic conquests. While the Normans were pillaging Italy, the Turks invaded Asia Minor. Emperor Romanos Diogenes moved the Byzantine army to meet them. At the Battle of Manzikert in 1071 CE, the Byzantine army was totally wiped out by the Turks. It was perhaps the most severe military disaster in Byzantine history. With this defeat, Anatolia fell into the hands of the Turks. Anatolia had been the heartland of the Byzantine Empire, the home of most of its soldiers and farmers. This defeat at Manzikert meant that the theme system, which had effectively supplied Byzantium with its army, was destroyed. The Byzantine Empire was now vulnerable to conquest.


Battle of Manzikert. In this 15th-century French miniature depicting the Battle of Manzikert, the combatants are clad in contemporary western European armor.

The brunt of the battle was borne by the professional soldiers from the eastern and western tagmata, as large numbers of mercenaries and Anatolian levies fled early and survived the battle. The fallout from Manzikert was disastrous for the Byzantines, resulting in civil conflicts and an economic crisis that severely weakened the Byzantine Empire’s ability to adequately defend its borders. This led to the mass movement of Turks into central Anatolia—by 1080, an area of 78,000 square kilometers (30,000 sq. miles) had been gained by the Seljuk Turks. It took three decades of internal strife before Alexius I (1081 to 1118) restored stability to Byzantium. Historian Thomas Asbridge says, “In 1071, the Seljuqs crushed an imperial army at the Battle of Manzikert (in eastern Asia Minor), and though historians no longer consider this to have been an utterly cataclysmic reversal for the Greeks, it still was a stinging setback.” It was the first time in history a Byzantine emperor had become the prisoner of a Muslim commander.

Years and decades later, Manzikert came to be seen as a disaster for the empire; later sources, therefore, greatly exaggerate the numbers of troops and the number of casualties. Byzantine historians would often look back and lament the “disaster” of that day, pinpointing it as the moment the decline of the empire began. It was not an immediate disaster, but the defeat showed the Seljuks that the Byzantines were not invincible—they were not the unconquerable, millennium-old Roman Empire (as both the Byzantines and Seljuks still called it). The usurpation of Andronikos Doukas also politically destabilized the empire, and it was difficult to organize resistance to the Turkish migrations that followed the battle.