The struggle for Constantinople was a complex series of conflicts following the dissolution of the Byzantine Empire in the aftermath of the Fourth Crusade in 1204, fought between the Latin Empire established by the Crusaders, various Byzantine successor states, and foreign powers such as the Second Bulgarian Empire and Sultanate of Rum, for control of Constantinople and supremacy within the former imperial territories.
At the time of the Fourth Crusade, the Byzantine Empire was already divided by internal revolts. In the aftermath of the Crusader sack of Constantinople, the empire was dissolved into a patchwork of territories held by various pretenders and warlords. The former Byzantine emperors Alexios III and Alexios V both aspired to retake the capital, though were defeated by the Latins. The early years after 1204 saw the rise and fall of numerous Byzantine statelets; the Latins managed to defeat warlords such as Leo Sgouros but were unable to halt the formation of the more well-organized rump states of the Empire of Nicaea, Empire of Trebizond, and Despotate of Epirus. The prospect of a potential swift Latin conquest of the entire former empire's territories effectively ended when the Bulgarian ruler Kaloyan defeated the Latin army at the Battle of Adrianople (1205).
In the years 1205–1209, the Empire of Nicaea transitioned into a proper empire-in-exile, with Theodore Laskaris crowned as emperor by a self-appointed Ecumenical Patriarch of Constantinople-in-exile. The Nicene emperor and his patriarch were not accepted as legitimate by the other Byzantine pretenders. An attempted two-front attack on both Epirus and Nicaea by the Latin emperor Robert of Courtenay in 1223/1224 ended in disaster for the latter and the Latin Empire thereafter only survived the following decades through the rivalry between its enemies. In 1224, Theodore Komnenos Doukas of Epirus captured Thessalonica, the second most important city of the former empire. Komnenous Doukas likewise had himself crowned emperor, establishing the Empire of Thessalonica, and came close to recapturing Constantinople before being defeated by Bulgaria at the Battle of Klokotnitsa in 1230.
After Klokotnitsa, Ivan Asen II of Bulgaria aspired to himself restore the Byzantine Empire, variously allying with and opposing the Nicene emperor John Doukas Vatatzes. In the early 1240s, Bulgaria was weakened by Ivan Asen's death and pressure from the Mongol Empire. During the Mongol invasion of Anatolia, Sultan Kaykhusraw II of Rum was—despite support by Christian forces sent by the Latin, Nicene, and Trapezuntine empires—defeated at the Battle of Köse Dağ (1243) and forced to submit as a Mongol vassal. The weakening of Bulgaria and Rum allowed John Doukas Vatatzes to rapidly expand into the Balkans. Although opposed by Bulgaria, the Thessalonian successor states, and the remaining Latin lords of Greece, the Nicenes under Michael Palaiologos ultimately captured Constantinople in 1261, restoring the Byzantine Empire.
Conflicts resulting from the struggle for Constantinople plagued much of the later reign of Michael Palaiologos (1261–1282). Despite challenges, Palaiologos managed to ensure the safety of the restored empire, which survived for two centuries under his descendants, until its fall in 1453.
The struggle for Constantinople was a complex series of conflicts following the dissolution of the Byzantine Empire in the aftermath of the Fourth Crusade in 1204, fought between the Latin Empire established by the Crusaders, various Byzantine successor states, and foreign powers such as the Second Bulgarian Empire and Sultanate of Rum, for control of Constantinople and supremacy within the former imperial territories.
At the time of the Fourth Crusade, the Byzantine Empire was already divided by internal revolts. In the aftermath of the Crusader sack of Constantinople, the empire was dissolved into a patchwork of territories held by various pretenders and warlords. The former Byzantine emperors Alexios III and Alexios V both aspired to retake the capital, though were defeated by the Latins. The early years after 1204 saw the rise and fall of numerous Byzantine statelets; the Latins managed to defeat warlords such as Leo Sgouros but were unable to halt the formation of the more well-organized rump states of the Empire of Nicaea, Empire of Trebizond, and Despotate of Epirus. The prospect of a potential swift Latin conquest of the entire former empire's territories effectively ended when the Bulgarian ruler Kaloyan defeated the Latin army at the Battle of Adrianople (1205).
In the years 1205–1209, the Empire of Nicaea transitioned into a proper empire-in-exile, with Theodore Laskaris crowned as emperor by a self-appointed Ecumenical Patriarch of Constantinople-in-exile. The Nicene emperor and his patriarch were not accepted as legitimate by the other Byzantine pretenders. An attempted two-front attack on both Epirus and Nicaea by the Latin emperor Robert of Courtenay in 1223/1224 ended in disaster for the latter and the Latin Empire thereafter only survived the following decades through the rivalry between its enemies. In 1224, Theodore Komnenos Doukas of Epirus captured Thessalonica, the second most important city of the former empire. Komnenous Doukas likewise had himself crowned emperor, establishing the Empire of Thessalonica, and came close to recapturing Constantinople before being defeated by Bulgaria at the Battle of Klokotnitsa in 1230.
After Klokotnitsa, Ivan Asen II of Bulgaria aspired to himself restore the Byzantine Empire, variously allying with and opposing the Nicene emperor John Doukas Vatatzes. In the early 1240s, Bulgaria was weakened by Ivan Asen's death and pressure from the Mongol Empire. During the Mongol invasion of Anatolia, Sultan Kaykhusraw II of Rum was—despite support by Christian forces sent by the Latin, Nicene, and Trapezuntine empires—defeated at the Battle of Köse Dağ (1243) and forced to submit as a Mongol vassal. The weakening of Bulgaria and Rum allowed John Doukas Vatatzes to rapidly expand into the Balkans. Although opposed by Bulgaria, the Thessalonian successor states, and the remaining Latin lords of Greece, the Nicenes under Michael Palaiologos ultimately captured Constantinople in 1261, restoring the Byzantine Empire.
Conflicts resulting from the struggle for Constantinople plagued much of the later reign of Michael Palaiologos (1261–1282). Despite challenges, Palaiologos managed to ensure the safety of the restored empire, which survived for two centuries under his descendants, until its fall in 1453.
Background
Byzantium and the Latins
The Byzantine (or Eastern Roman) Empire was the medieval continuation of the Roman Empire, ruled from Constantinople. Similar to the ancient Roman emperors, the Byzantine emperors considered themselves universal rulers, nominally ruling all Christendom. Although Byzantine territory gradually declined over the centuries, their claim to rule continued to be acknowledged by temporal and religious authorities in Western Europe, even if formal imperial control could not be restored. In the reign of Emperor Constantine V (r. 741–775), Byzantine efforts were concentrated on the Muslims and the Bulgars, and the defense of Italy was neglected, leading to the fall of the Exarchate of Ravenna, the main Byzantine administrative unit in Italy, to the Lombards in 751. The popes, technically Byzantine vassals, realized that Byzantine support was not a guarantee and instead began to rely on the major western kingdom, the Franks, for support against the Lombards. In 800, Pope Leo III crowned the Frankish king Charlemagne as emperor, laying the groundwork for the later Holy Roman Empire, severing the papacy's connection to the Byzantine Empire, and challenging Byzantium's claim to universal rule.
The Byzantines self-identified as Romans (Rhōmaîoi). Given that they themselves used Greek as both a vernacular and religious language, the common term used in Byzantium for westerners from the 11th century onwards was "Latins" (Latinoi), in reference to the church language of the Catholic Church. Westerners typically referred to the Byzantines as "Greeks". Relations between Byzantium and the west significantly deteriorated with the Great Schism of 1054, which ended communion between the Catholic and Eastern Orthodox churches. Although the Byzantines continued to consider the pope in Rome to be the most important patriarch in the pentarchy, Byzantine religious affairs thereafter became more isolated and reflective of their own customs. Byzantine writers routinely described Western Europeans as uncouth barbarians, while the westerners in turn viewed the Byzantines as effeminate and treacherous.
The Byzantine Empire was nearly driven out of Anatolia, which had traditionally provided the bulk of the empire's armies, by the Seljuk Empire in the 1070s. Emperor Alexios I Komnenos (r. 1081–1118) called for military aid from Pope Urban II, who responded by calling the First Crusade (1096–1099). Although successful in repelling Seljuk advances and restoring Byzantine control over large parts of Anatolia, the crusade generated new difficulties for the Byzantines. The Crusaders cared little that lands they sacked on their way to the Holy Land had been Byzantine merely a few decades prior. The First Crusade solidified the differences between Byzantium and the West and brought hostility to the popular level. When Crusaders under Bohemond of Taranto captured Antioch in 1098, the Crusaders did not return the city to the Byzantines and Bohemond went as far as to appoint a Latin patriarch in the city instead of recognizing the incumbent Orthodox patriarch, causing outcry in Constantinople. Over the course of the Crusades, Crusaders and other westerners (such as the Republic of Venice) were attracted by the splendor and wealth of Byzantium, but repeatedly enraged by Byzantine foreign policy.
Emperor Manuel I Komnenos (r. 1143–1180) unsuccessfully sought to reunify the Orthodox and Latin churches, and also tried to integrate the Byzantine Empire into the world of Latin states in the West and the Levant (the Crusader states) through diplomacy. These diplomatic efforts were largely unsuccessful, since the Latin polities began to view themselves as having a say in imperial politics and a strong anti-Latin sentiment grew in Byzantium, owing to Manuel's concessions and increasing Latin domination. Tensions in Constantinople reached a boiling point after Manuel's death, resulting in the 1182 Massacre of the Latins. The massacre was in 1185 followed by an invasion by the Norman Kingdom of Sicily which resulted in a brutal sack of Thessalonica, deepening the rift between Byzantium and the West. At the same time as tensions were increasing, Byzantium under the Komnenos (1081–1185) and Angelos (1185–1204) dynasties was experiencing a collapse of central authority and manpower issues resulting from an increasingly powerful aristocracy. Despite the decline, Constantinople remained the greatest city in Christendom. During the Third Crusade (1189–1192), the Holy Roman Emperor Frederick Barbarossa led an army through the Byzantine Empire. The march caused Byzantine emperor Isaac II Angelos (r. 1185–1195) to panic, believing Barbarossa also planned to overthrow Byzantium. Isaac imprisoned several Latin citizens in Constantinople and concluded a secret alliance with the Muslim ruler Saladin, promising to delay and destroy Barbarossa's army in return for concessions in the Holy Land. Although full war was avoided, the mistreatment sustained by Barbarossa and his army was long remembered in the West.
The Fourth Crusade (1202–1204)
Pope Innocent III called for a Fourth Crusade in 1198 and a Crusader army assembled at Venice in 1202. The leader of the crusade, Boniface of Montferrat, lobbied for a diversion to Constantinople instead of attacking the Holy Land, and succeeded in convincing the crusade leadership as well as the Republic of Venice when it became apparent that the Crusaders had less money and soldiers than had been anticipated. The legitimization of the attack was provided through Alexios IV Angelos, a Byzantine prince and son of Isaac II Angelos, who had traveled to the West and asked for aid in supplanting his uncle Alexios III Angelos (r. 1195–1203, who had usurped Isaac II) on the Byzantine throne. Although Pope Innocent tried to dissuade an attack on Constantinople, writing to the Crusaders in April 1203 that "it is not your business to judge the crimes of Constantinople" and Venice had signed a treaty with Alexios III in 1198, promising to be faithful allies, the plans proceeded. Priests accompanying the crusade justified an attack on Christian Byzantium since "the Greeks are schismatics, worse than the Jews".
The Fourth Crusade reached Constantinople on 24 June 1203. The Crusaders marveled at the vastness of the city and the Byzantines were astonished by the size of the army. Alexios III offered to pay them to leave, though the Crusaders demanded his immediate abdication. When Alexios IV was paraded in front of the city's walls, the populace of Constantinople rejected the young prince. Following several Crusader assaults on the city, Alexios III fled Constantinople in the night of 17/18 July. The confused court and high command of the empire restored the deposed Isaac II to the throne, disarming the Crusaders' pretext of restoring legitimacy to the Byzantine government. Alexios IV was made co-emperor under pressure from the Crusaders on 1 August 1204. Alexios IV immediately began paying the Crusders, resorting to plundering churches, and promised to submit the empire's church to the Pope, though no action was taken to achieve this. The Crusaders stayed in Constantinople, claiming that it was too late in the season for them to depart, and Alexios IV agreed to host them until March 1204. As the westerners mistreated the locals and the locals resisted in turn, Alexios IV began to be regarded as an "abomination" by his subjects. A Constantinopolitan resistance against the Latins formed in late 1203, in which the nobleman Alexios Doukas became a leading figure. As Isaac II laid dying of natural causes, the populace elected a new (unwilling) emperor in Hagia Sophia on 27 January 1204, Nicholas Kanabos. A few days later, Alexios Doukas had both Alexios IV and Kanabos arrested and executed. In their stead, Doukas was proclaimed emperor in Hagia Sophia on 5 February, becoming Alexios V.
After several skirmishes, a Crusader assault on 12–13 April made Alexios V also flee the capital. Over the course of the next three days, the Crusaders brutally sacked Constantinople. Over its centuries as the greatest Christian city, Constantinople had accumulated vast wealth and innumerable holy relics, now looted or destroyed. The common people were slaughtered and raped indiscriminately. In Hagia Sophia, the Latins hacked the great altar to pieces and had a French prostitute dressed in the patriarch's robes to put on a show. The tombs of past Byzantine emperors were plundered and desecrated, including those of Justinian I and Basil II. As a result of numerous great fires started during the Crusaders' stay in the city, about a sixth of Constantinople was a burned ruin and the rest was depopulated and stripped of anything valuable. The Crusaders wrote to Pope Innocent after the sack, calling it "divine justice" against the schismatic Byzantines, and requested that the defense of their conquered lands in Byzantium be sanctioned as an "ongoing crusade" so that further Crusaders would arrive and bolster their forces.
Collapse and consolidation (1204–1209)
Dissolution of the empire (1204)
Before the sack of Constantinople, the Crusaders and Venetians agreed that a new emperor would be elected by a college of six Venetians and six Crusaders. On 9 May 1204, they elected the Crusader Baldwin of Flanders as Alexios V's successor. Emperor Baldwin I was crowned in the Hagia Sophia in an imitation of Byzantine coronations on 16 May. The Venetian subdeaconThomas Morosini was made the first Catholic Patriarch of Constantinople. The Venetians and Crusaders concluded a treaty, the Partitio terrarum imperii Romaniae, in which the Byzantine Empire's territory was partitioned. The emperor received a quarter of Constantinople and the empire, with his lands placed in Anatolia and parts of Thrace. The Venetians and other Crusaders each received half of the remainder of the empire, to hold as imperial fiefs. Crusader holdings were primarily in Greece whereas the Venetians fiefs were to consist of islands in the Aegean Sea, some ports, and Epirus.
Baldwin's empire, which the Byzantines dubbed the 'Latin Empire', at first controlled merely Constantinople and its immediate surroundings. Following the sack of the city, the rest of the Byzantine Empire had unraveled into a patchwork of bewildered imperial governors, foreign invaders, rebels, and pretenders. Baldwin's two foremost rivals were the former emperors Alexios III and Alexios V, both of whom had survived the initial Crusader attacks. Alexios V ruled eastern Thrace from Tzurulum and Alexios III, based in Mosynopolis, ruled both western Thrace and the lands surrounding Thessalonica. A third claimant emperor had also risen in the far east, Alexios Komnenos, who had seized Trebizond and the surrounding Black Sea shoreline with the aid of Tamar of Georgia, establishing what historians refer to as the 'Empire of Trebizond'. This Alexios was the grandson of Andronikos I Komnenos, who had reigned as Byzantine emperor 1183–1185.
Other than the imperial claimants, several territories fell under the control of local warlords. The rebel magnate Leo Sgouros controlled large parts of Greece around the cities of Nafplio, Corinth, and Thebes. Much of northwestern Anatolia was held by Theodore Laskaris, Alexios III's son-in-law. Other noteworthy rebel magnates included Leo Gabalas (who controlled Rhodes) and three competing magnates in the Meander valley: Theodore Mangaphas (around Philadelphia), Manuel Maurozomes (in the east), and Sabas Asidenos (around Priene). After the sack of Constantinople, Mangaphas proclaimed himself emperor, becoming a fourth Byzantine imperial claimant. The island of Crete had fallen under Latin control before the sack, being given to Boniface of Montferrat as pronoia by Alexios IV and now held by his men. In southern Anatolia, an Italian adventurer named Aldobrandini seized the city of Attaleia.