The Byzantine Empire

Emperor Diocletian establishes the Tetrarchy system, dividing the Roman Empire into four administrative regions with two senior emperors (Augusti) and two junior emperors (Caesares). This administrative reform laid the groundwork for the eventual permanent division of the empire into Eastern and Western halves.

Constantine I defeats Maxentius at the Battle of the Milvian Bridge and converts to Christianity after reportedly seeing a vision of the Chi-Rho symbol. This victory consolidated his power and marked the beginning of Christianity's rise to prominence in the Roman Empire, fundamentally changing the empire's religious landscape.

Constantine I issues the Edict of Milan, granting religious tolerance throughout the empire and effectively ending the persecution of Christians. This landmark decree allowed Christianity to flourish openly and set the stage for its eventual adoption as the empire's official religion.

Constantine I founds Constantinople (modern-day Istanbul) as the 'New Rome' on the site of the ancient Greek city of Byzantia. This strategically located city would serve as the capital of the Eastern Roman Empire for over a thousand years, controlling the vital trade routes between Europe and Asia.

Emperor Theodosius I makes Christianity the official religion of the Roman Empire through the Edict of Thessalonica. This decree marked the end of traditional Roman polytheism and established Nicene Christianity as the sole authorized religion, fundamentally transforming the empire's cultural and religious identity.

Upon the death of Theodosius I, the Roman Empire is permanently divided between his two sons: Arcadius receives the Eastern Empire and Honorius the Western Empire. This division marked the definitive split that would lead to the development of the Byzantine Empire as a distinct political entity.

Alaric I and his Visigothic army sack Rome, shocking the civilized world and demonstrating the vulnerability of the Western Roman Empire. This event marked a turning point in Roman history and highlighted the growing strength of barbarian tribes against imperial authority.

The Vandals under King Genseric sack Rome for fourteen days, further weakening the Western Roman Empire. Unlike Alaric's earlier sack, this was a more systematic looting that stripped the city of many of its treasures and demonstrated the continued decline of Western Roman power.

Romulus Augustulus, the last Western Roman Emperor, is deposed by the Germanic chieftain Odoacer, marking the traditional end of the Western Roman Empire. The Eastern Roman Empire, later known as the Byzantine Empire, continued to exist and would claim to be the legitimate continuation of Rome.

Justinian I becomes Emperor of the Eastern Roman Empire and begins his ambitious program to reconquer the lost Western territories. His reign would mark the height of Byzantine power and influence, characterized by military conquests, legal reforms, and architectural achievements.

The Nika Riots erupt in Constantinople, nearly toppling Justinian's government. The riots, which began as chariot racing faction disputes, evolved into a major political uprising that threatened to overthrow the emperor. Justinian's decision to stay and fight, influenced by Empress Theodora, ultimately saved his reign.

Byzantine general Belisarius completes the conquest of the Vandal Kingdom in North Africa, restoring Byzantine control over this wealthy province. This successful campaign demonstrated Byzantine military capability and marked the beginning of Justinian's ambitious reconquest of former Western Roman territories.

Justinian promulgates the Corpus Juris Civilis (Body of Civil Law), a comprehensive codification of Roman law that would influence legal systems for centuries. This monumental legal work preserved and systematized Roman jurisprudence, becoming the foundation for legal systems throughout Europe.

Belisarius captures Rome from the Ostrogoths, beginning the Gothic War that would eventually restore much of Italy to Byzantine control. This campaign was part of Justinian's broader effort to reconquer the Western Roman Empire and restore imperial unity under Constantinople.

The Hagia Sophia is completed in Constantinople under Justinian's patronage, becoming the largest cathedral in the world and a masterpiece of Byzantine architecture. This architectural marvel served as the center of Eastern Orthodox Christianity and symbolized the power and glory of the Byzantine Empire.

The Justinianic Plague, likely bubonic plague, strikes the Byzantine Empire, killing an estimated 25-50 million people across the Mediterranean world. This devastating pandemic weakened the empire's military and economic capabilities, hampering Justinian's reconquest efforts and marking the beginning of a period of decline.

The Gothic War concludes with Byzantine victory, restoring most of Italy to imperial control. However, the prolonged conflict had devastated the Italian peninsula and drained the empire's resources, making it difficult to maintain control over the reconquered territories.

Emperor Justinian I dies, ending one of the most significant reigns in Byzantine history. His death marked the end of the last serious attempt to restore the full extent of the Roman Empire, and his successors would face increasing pressure from new enemies on multiple fronts.

The Lombards invade Italy under King Alboin, conquering much of northern and central Italy from the Byzantines. This invasion effectively ended Byzantine control over most of Italy and established the Lombard Kingdom, which would persist for over two centuries.

Emperor Heraclius begins his reign, inheriting an empire under severe pressure from the Sassanid Persians and various barbarian groups. His reign would be marked by military reforms, religious policies, and the beginning of the transformation from the Eastern Roman Empire into what historians call the Byzantine Empire.

The Sassanid Persians capture Jerusalem, taking the True Cross and deporting thousands of Christians. This devastating loss shocked the Christian world and represented the nadir of Byzantine fortunes during the Byzantine-Sassanid War, prompting Heraclius to launch his famous counteroffensive.

Heraclius defeats the Sassanid Persians at the Battle of Nineveh, beginning the collapse of the Persian Empire and the recovery of Byzantine territories. This victory marked the turning point in the long Byzantine-Sassanid conflict and restored Byzantine prestige in the Near East.

The Treaty of Peace is signed between Byzantium and Persia, restoring all conquered territories to their pre-war boundaries and returning the True Cross to Jerusalem. This treaty ended the devastating 26-year war but left both empires exhausted and vulnerable to the emerging Arab threat.

Arab Muslim forces defeat the Byzantine army at the Battle of Yarmuk, leading to the permanent loss of the Levant to the expanding Islamic Caliphate. This decisive defeat marked the beginning of massive territorial losses that would transform the Byzantine Empire into a primarily Anatolian and Balkan state.

Arab forces capture Jerusalem from the Byzantines, with Caliph Umar ibn al-Khattab personally receiving the city's surrender. This loss was particularly devastating to the Christian Byzantine Empire, as Jerusalem held immense religious significance and had been recently recovered from the Persians.

The Arab conquest of Egypt is completed with the fall of Alexandria, depriving the Byzantine Empire of one of its wealthiest and most important provinces. Egypt's loss eliminated a major source of grain and tax revenue, fundamentally altering the empire's economic foundation.

The first Arab siege of Constantinople begins, marking the Islamic Caliphate's attempt to capture the Byzantine capital. The siege would last for several years and represent the greatest threat to the empire's survival since its foundation, testing Byzantine naval and defensive capabilities.

The first Arab siege of Constantinople ends in failure, with the Byzantine navy's use of Greek fire proving decisive in repelling the Islamic fleet. This victory preserved the empire's capital and demonstrated the effectiveness of Byzantine naval technology and defensive strategies.

Emperor Justinian II is deposed in a coup, beginning a period of political instability known as the Twenty Years' Anarchy. This period of frequent regime changes weakened the empire's ability to respond effectively to external threats and internal challenges.

Leo III becomes emperor, founding the Isaurian dynasty and beginning the period of Iconoclasm. His reign marked the start of a new phase in Byzantine history, characterized by military reforms, administrative changes, and religious controversy over the use of religious images.

The second Arab siege of Constantinople begins under Caliph Sulayman ibn Abd al-Malik, representing another major attempt to capture the Byzantine capital. This siege would prove to be the last serious Arab attempt to conquer Constantinople and eliminate the Byzantine Empire.

The second Arab siege of Constantinople ends in complete failure, with the Arab army and navy suffering devastating losses. This victory secured the empire's survival and marked the beginning of a Byzantine recovery that would last for several centuries.

Emperor Leo III issues the first iconoclastic edict, beginning the systematic destruction of religious images throughout the empire. This policy created a major religious and political crisis that would divide Byzantine society for over a century and strain relations with the papacy.

The Byzantine army defeats the Bulgars at the Battle of Akroinon, halting their advance into Anatolia and demonstrating the empire's military recovery. This victory marked the beginning of a period of Byzantine expansion and the gradual recovery of territories lost to various enemies.

Empress Irene restores the veneration of icons at the Second Council of Nicaea, temporarily ending the first period of Iconoclasm. This decision restored religious unity within the empire but created new tensions with iconoclastic elements in the military and administration.

Charlemagne is crowned Emperor of the Romans by Pope Leo III, creating a rival claim to Roman imperial authority and challenging Byzantine legitimacy. This event marked the beginning of the complex relationship between the Byzantine and Western European empires.

Emperor Leo V restores Iconoclasm, beginning the second iconoclastic period that would last until 843. This renewal of the religious controversy demonstrated the continued divisions within Byzantine society over the role of religious images in Christian worship.

Empress Theodora definitively restores the veneration of icons, ending Iconoclasm permanently on what becomes known as the 'Triumph of Orthodoxy.' This event marked the end of over a century of religious controversy and established the theological foundation for later Byzantine culture.

The Photian Schism begins when Patriarch Photios I of Constantinople and Pope Nicholas I excommunicate each other, creating a major rift between Eastern and Western Christianity. This conflict highlighted the growing theological and political differences between the Byzantine and Roman churches.

Saints Cyril and Methodius begin their mission to the Slavs, creating the Glagolitic alphabet and translating Christian texts into Slavonic. Their work laid the foundation for the Christianization of the Slavic peoples and the spread of Byzantine cultural influence in Eastern Europe.

The Bulgarian Khan Boris I converts to Christianity, bringing the First Bulgarian Empire into the Byzantine sphere of influence. This conversion had profound implications for the balance of power in the Balkans and the spread of Orthodox Christianity among the Slavic peoples.

Basil I becomes emperor, founding the Macedonian dynasty that would rule for nearly two centuries. His reign began a period of Byzantine revival known as the Macedonian Renaissance, characterized by military success, territorial expansion, and cultural flourishing.

Emperor Basil II begins his personal rule after eliminating his co-emperor and rival claimants, starting the most successful period of the Macedonian dynasty. His reign would be marked by the complete conquest of Bulgaria and the expansion of Byzantine power to its medieval zenith.

Prince Vladimir I of Kiev converts to Orthodox Christianity and marries Anna Porphyrogenita, sister of Emperor Basil II. This marriage alliance brought the Kievan Rus into the Byzantine sphere and led to the Christianization of Russia, with profound long-term consequences for Eastern European history.

The Great Schism occurs when Patriarch Michael I Cerularius and Cardinal Humbert excommunicate each other, formally dividing Eastern Orthodox and Roman Catholic Christianity. This event marked the definitive split between the Eastern and Western churches that persists to this day.

The Seljuk Turks defeat Emperor Romanos IV at the Battle of Manzikert, capturing the emperor and opening Anatolia to Turkish settlement. This devastating defeat marked the beginning of the end of Byzantine control over Asia Minor and fundamentally altered the empire's strategic position.

Emperor Alexios I Komnenos appeals to Pope Urban II for military assistance against the Seljuk Turks, inadvertently triggering the First Crusade. This request for help would have unintended consequences, as the Crusades would eventually pose as much threat to Byzantium as they did aid.

The armies of the First Crusade arrive in Constantinople, creating tension between the Crusaders and Emperor Alexios I. Despite initial cooperation, the relationship between Byzantium and the Crusader states would become increasingly strained over territorial and religious differences.

The Crusaders capture Antioch, establishing the Principality of Antioch without returning it to Byzantine control as previously agreed. This betrayal marked the beginning of the deterioration of Byzantine-Crusader relations and the loss of important former Byzantine territories.

John II Komnenos becomes emperor, continuing his father's policies of military reform and territorial recovery. His reign would be marked by successful campaigns against the Turks in Anatolia and efforts to reassert Byzantine authority over the Crusader states.

Manuel I Komnenos becomes emperor, beginning an ambitious reign that would see both the height and the beginning of the decline of the Komnenian restoration. His aggressive foreign policy and military campaigns would ultimately overextend the empire's resources.

The Second Crusade passes through Byzantine territory, creating new tensions between Emperor Manuel I and the Crusader leaders. The failure of this Crusade further strained Byzantine-Western relations and demonstrated the limitations of Crusader military effectiveness.

The Seljuk Turks defeat Manuel I at the Battle of Myriokephalon, ending Byzantine hopes of reconquering central Anatolia. This defeat has been called the 'Manzikert of the Komnenian period' and marked the definitive end of Byzantine expansion in Asia Minor.

Saladin recaptures Jerusalem from the Crusaders, prompting the Third Crusade and further involving Byzantium in Crusader politics. The loss of Jerusalem shifted the balance of power in the Near East and affected Byzantine relations with both Muslims and Crusaders.

The Third Crusade passes through Byzantine territory, with Emperor Isaac II Angelos struggling to manage the relationship with the Crusader armies. The passage of these large military forces created significant logistical and diplomatic challenges for the empire.

The Fourth Crusade is diverted to Constantinople, beginning the siege that would lead to the sack of the city. This diversion, orchestrated by Venetian interests and Byzantine political intrigue, would prove catastrophic for the empire.

Theodore I Laskaris establishes the Empire of Nicaea as a Byzantine successor state, maintaining the claim to be the legitimate Roman Empire. This state would serve as the primary center of Byzantine resistance and eventual restoration.

The Crusaders sack Constantinople, ending the Byzantine Empire and establishing the Latin Empire. This catastrophic event scattered the Byzantine nobility and divided the empire's territories among Western European nobles, fundamentally altering the political landscape of the Eastern Mediterranean.

Michael VIII Palaiologos recaptures Constantinople from the Latin Empire, restoring the Byzantine Empire after 57 years of Western rule. This restoration marked the beginning of the final period of Byzantine history, though the empire would never fully recover its former power.

The Council of Lyon attempts to reunite the Eastern and Western churches under papal authority, with Emperor Michael VIII accepting the union for political reasons. This controversial decision created internal opposition and failed to achieve lasting reconciliation between the churches.

Andronikos II becomes emperor, beginning a long reign marked by economic decline, territorial losses, and civil wars. His reign would see the empire's continued weakening and the rise of new threats, particularly from the Ottoman Turks.

The Catalan Company, a mercenary force, begins devastating raids in Byzantine territory after a payment dispute. These mercenaries would ravage Anatolia and Thrace for several years, further weakening the empire's already precarious position.

The Ottoman Turks capture their first European territory at Gallipoli, establishing a permanent foothold in Europe. This acquisition marked the beginning of Ottoman expansion into the Balkans and posed a direct threat to the Byzantine Empire's remaining territories.

John V Palaiologos travels to Rome and converts to Catholicism in a desperate attempt to secure Western military aid against the Ottomans. This controversial act failed to produce the desired assistance and created further religious divisions within the empire.

Bayezid I begins the first Ottoman siege of Constantinople, bringing the Byzantine capital under direct threat. Although this siege would be lifted due to Timur's invasion of Anatolia, it demonstrated the empire's extreme vulnerability.

The Ottomans defeat a Crusader army at the Battle of Nicopolis, eliminating the last major Western attempt to halt Ottoman expansion in the Balkans. This victory secured Ottoman control over much of the Balkans and left Byzantium increasingly isolated.

Timur defeats the Ottomans at the Battle of Ankara, capturing Sultan Bayezid I and temporarily saving the Byzantine Empire from conquest. This unexpected reprieve gave Byzantium a few more decades of existence during the Ottoman interregnum.

The Council of Ferrara-Florence attempts to reunite the Eastern and Western churches, with Emperor John VIII accepting the union in exchange for promised military aid. This controversial decision created significant opposition within the empire and failed to produce effective Western assistance.

Constantine XI Palaiologos becomes the last Byzantine Emperor, inheriting an empire reduced to Constantinople and a few surrounding territories. His reign would be entirely consumed by the final Ottoman siege and the empire's ultimate destruction.

Sultan Mehmed II begins the final siege of Constantinople with a massive army and advanced artillery, including the famous great cannon designed by Orban. This siege would employ the most advanced military technology of the time and represent the culmination of Ottoman expansion.

Constantinople falls to the Ottomans after a final assault, ending the Byzantine Empire after over 1,000 years of existence. Emperor Constantine XI dies fighting on the walls, and the city is sacked by Ottoman forces, marking the end of the last remnant of the Roman Empire.