Constantine the Great dedicates Byzantium as Nova Roma, the new imperial capital on the Bosphorus.

Constantine dies near Nicomedia after baptism; the empire is divided among his three sons.

Constantius II completes the imperial mausoleum church begun under Constantine; burial place of emperors for seven centuries.

The 'Great Church' of Constantinople is dedicated under Constantius II; it would twice burn and be rebuilt.

Julian, the last pagan emperor, dies of a wound on campaign beyond the Tigris; his successor Jovian cedes Nisibis to Persia.

Fleeing the Huns, Gothic peoples are admitted into Thrace; mistreatment by Roman officials drives them to revolt.

The Gothic cavalry destroys the eastern field army; Emperor Valens is killed, a defeat Ammianus compared to Cannae.

The second ecumenical council confirms Nicene orthodoxy and completes the creed; Constantinople is ranked second only to Rome.

Theodosius I raises the Egyptian obelisk of Thutmose III on the spina of the Hippodrome, on a sculpted marble base.

The empire is permanently divided between Arcadius in the East and Honorius in the West.

The great preacher-patriarch of Constantinople is deposed and exiled after clashing with the empress Eudoxia; he dies in 407.

The Visigoths sack Rome for three days — the first fall of the city in eight centuries, felt as an omen across both empires.

The praetorian prefect Anthemius completes the great land walls of Constantinople, which will repel every besieger for a thousand years.

Theodosius II endows the Pandidakterion with chairs of Greek and Latin grammar, rhetoric, law and philosophy.

The third ecumenical council condemns Nestorius and affirms the Virgin as Theotokos, 'God-bearer'.

Theodosius II issues the first official compilation of imperial law since the tetrarchy, binding in both halves of the empire.

A great earthquake throws down 57 towers of the Theodosian Walls with Attila approaching; the city rebuilds them in sixty days.

The fourth ecumenical council defines Christ in two natures; Egypt and Syria largely reject it, opening a lasting schism.

The consul Studius founds the monastery of St John the Forerunner, later the most influential monastic house in the capital.

The vast joint expedition against Vandal Carthage is destroyed by fire-ships; the treasury is emptied for a generation.

Odoacer deposes Romulus Augustulus and returns the western regalia to Constantinople, leaving one Roman emperor.

The silentiary Anastasius takes the throne; his fiscal reforms will leave the treasury 320,000 pounds of gold in credit.

Anastasius completes the 56-km wall from the Black Sea to the Marmara as an outer defence for the capital's hinterland.

An earthquake and fire kill perhaps 250,000 in Antioch during the Ascension crowds; the city never fully recovers.

Justinian's commission under Tribonian publishes the new code of imperial law, first part of the Corpus Iuris Civilis.

Circus factions unite in revolt and half the capital burns; Justinian, steeled by Theodora, has some 30,000 killed in the Hippodrome.

Belisarius lands in Africa and destroys the Vandal kingdom in two battles, Ad Decimum and Tricamarum, within months.

The Digest distils nine centuries of Roman jurisprudence; with the Institutes it completes the core of Justinian's legal corpus.

A volcanic dust veil dims the sun for over a year — 'the sun gave forth its light without brightness' — bringing cold and failed harvests.

Justinian dedicates Anthemius and Isidore's domed Great Church, the largest building in the world: 'Solomon, I have outdone thee.'

The Persian king Khosrow I storms and burns Antioch, deporting its people to a new city near Ctesiphon.

Bubonic plague, arrived from Egypt, kills a large fraction of Constantinople's population and recurs for two centuries.

The octagonal church with its mosaic panels of Justinian and Theodora is consecrated in newly reconquered Italy.

Narses destroys the Ostrogothic army and its king Totila, sealing the Roman reconquest of Italy.

The fifth ecumenical council condemns the Three Chapters in a bid to reconcile the anti-Chalcedonian East.

A severe earthquake cracks the dome of Hagia Sophia, which collapses the following May; a steeper dome is built by 562.

Justinian dies after 38 years; the empire he doubled is exhausted by war, plague and debt.

Within three years of Justinian's death the Lombards overrun much of Italy, reducing imperial holdings to coastal enclaves.

The city credits its deliverance to St Demetrius; the Miracles of St Demetrius record the age of Slav settlement in the Balkans.

The army mutinies under Phocas; Maurice and his sons are executed, and Persia seizes the pretext for total war.

Sailing from Africa, Heraclius overthrows Phocas amid a collapsing eastern front and begins remaking the empire.

After a brief siege the Persians sack Jerusalem and carry off the relic of the True Cross.

With Heraclius away, Avars and Persians besiege the capital; its deliverance is ascribed to the Theotokos, celebrated in the Akathist hymn.

Heraclius crushes the Persian army deep in Mesopotamia; within a year Khosrow II is murdered and the True Cross returned.

The Arab armies annihilate the imperial field force after six days on the Yarmouk; Syria is lost permanently.

Heraclius dies broken by the Arab conquests; a succession crisis among his heirs ends with his grandson Constans II.

The Arab conquest of Egypt is complete; the empire loses its richest province and its grain.

The new Arab fleet defeats the imperial navy off Lycia, with Constans II barely escaping — Arab sea power arrives.

Constans II visits Rome — the last reigning emperor to do so for centuries — and settles his court at Syracuse until his murder in 668.

A four-year Arab blockade of the capital is broken with the help of a new weapon, Greek fire.

The sixth ecumenical council condemns Monotheletism, closing the christological compromises of the war years.

After defeating Constantine IV, Asparuh's Bulgars are recognized by treaty — the founding of the Bulgarian state.

The council issues the canons the fifth and sixth councils lacked; Rome rejects several, straining East-West relations.

Leontius deposes Justinian II and slits his nose; two decades of coups — the 'Twenty Years' Anarchy' — begin.

The Arabs take Carthage for good; Byzantine Africa, Belisarius' conquest, is lost after 165 years.

With Bulgar help the rhinotmetos re-enters the city through an aqueduct and takes a terrible revenge on his enemies.

The strategos of the Anatolikon seizes the throne just as the Arab grand army arrives, founding the Isaurian dynasty.

Greek fire, a hard winter, and Bulgar attacks destroy the caliphate's greatest expedition; the tide of conquest breaks at the walls.

Leo III moves against the veneration of icons; the destruction of the Chalke Gate image opens a century of controversy.

Leo III and Constantine V rout the Arab invasion force in Phrygia, the first decisive field victory of the reconquest era.

A great earthquake damages the walls and churches of Constantinople; repairs are funded by a new tax.

Leo III publishes a short Greek law handbook 'in a more philanthropic direction', replacing mutilation for death in many crimes.

The last great outbreak of the Justinianic plague empties the capital, which is repopulated from the Aegean islands.

The Lombards take Ravenna, ending the exarchate; the popes turn from Constantinople to the Franks.

Constantine V's council of 338 bishops condemns icon veneration — later repudiated as a 'headless' pseudo-council.

Constantine V rebuilds the great aqueduct, cut by the Avars in 626, with thousands of workmen from across the empire.

Under the empress Irene the seventh ecumenical council restores the veneration of icons.

The empress-mother has her son blinded in the purple chamber where he was born, and rules alone — the first reigning empress.

The pope crowns Charlemagne 'Emperor of the Romans' — to Constantinople, an act of usurpation with a long shadow.

Khan Krum annihilates the imperial army in the Balkan passes; Nikephoros I is killed and his skull made a drinking cup.

Leo V, reading the defeats as God's judgement, reinstates the ban on icons at a council in Hagia Sophia.

Thomas besieges Constantinople for a year with wide support in Anatolia; the civil war exhausts the themes' defences.

Andalusian exiles seize Crete and make it a corsair emirate; the Aegean becomes a raiding ground for over a century.

Caliph Mu'tasim storms Amorion, cradle of the reigning dynasty; the 42 Martyrs of Amorion become icons of resistance.

The empress-regent Theodora restores the icons for good; the event is still commemorated on the first Sunday of Lent.

Bardas refounds higher learning in the palace under Leo the Mathematician — the spark of the Macedonian renaissance.

A fleet of the Rus' appears from the Black Sea and ravages the capital's suburbs — the first act of Russo-Byzantine history.

The Thessalonican brothers carry a Slavonic liturgy and new alphabet to Moravia — the foundation of Slavic letters.

Khan Boris accepts baptism from Constantinople, taking the name Michael after his imperial godfather.

The former groom murders his patron Michael III and takes the throne; his house will reign for 189 years.

Basil I's 'New Church' in the palace grounds, with five gilded domes, sets the model for the cross-in-square middle Byzantine church.

Leo the Wise completes the 60-book Greek recasting of Justinian's law — the definitive legal corpus of the middle empire.

The renegade Leo of Tripoli storms the empire's second city from the sea and carries off some 22,000 captives.

Leo VI's uncanonical fourth marriage, made to legitimize the future Constantine VII, splits the church for a decade.

Tsar Symeon crushes the imperial army near Anchialus — one of the bloodiest defeats of the century — and claims the imperial title.

On Symeon's death his son Peter makes peace, marrying the emperor's granddaughter and receiving recognition as tsar.

Igor of Kiev's fleet is destroyed by Greek fire off the Bosphorus; treaty and trade follow within three years.

Romanos I is deposed by his own sons, who are in turn overthrown; Constantine VII at last rules alone at 39.

Constantine VII compiles his confidential handbook of statecraft and ethnography for his son — a unique window on the tenth-century world.

Nikephoros Phokas storms Chandax after a winter siege, ending 135 years of corsair rule in the Aegean.

St Athanasius founds the first great coenobitic monastery of the Holy Mountain with Nikephoros Phokas' patronage.

Tarsos and Mopsuestia fall and Cyprus returns to full imperial control; the road to Syria lies open.

After three centuries under Islam, the great city of the East returns to the empire.

John Tzimiskes and the empress Theophano have the soldier-emperor murdered in his bedchamber.

John Tzimiskes drives the Rus' from Bulgaria after a three-month siege; eastern Bulgaria is annexed.

Vladimir of Kiev accepts baptism and marries the porphyrogenita Anna; Rus' enters the Byzantine religious world.

An earthquake brings down the western arch and dome of Hagia Sophia; the Armenian architect Trdat rebuilds it by 994.

The great encyclopedic lexicon of some 30,000 entries preserves fragments of hundreds of lost ancient works.

Basil II traps the Bulgarian army in the Belasica passes; tradition holds the captives were blinded, 99 of every 100.

Bulgaria submits entirely; for the first time since the Slav migrations the whole Balkan peninsula is imperial.

The Bulgar-Slayer dies after 49 years of sole rule, leaving the empire at its medieval zenith — and without an heir of substance.

The aging porphyrogenita Zoe raises and discards emperors; palace politics consume the surplus Basil left.

Yaroslav's fleet is destroyed off the Bosphorus by Greek fire and storm — the final war between Rus' and the empire.

Cardinal Humbert lays a bull of excommunication on the altar of Hagia Sophia; Patriarch Keroularios anathematizes the legates in turn.

The eastern armies proclaim Isaac Komnenos; the military aristocracy takes the throne from the civil bureaucracy.

Michael Psellos composes his brilliant, gossiping portrait gallery of the emperors from Basil II to his own day.

The Seljuk sultan Alp Arslan captures Romanos IV; the civil wars that follow, more than the battle, hand Anatolia to the Turks.

Robert Guiscard takes the last Byzantine city in Italy after a three-year siege, ending five centuries of imperial Italy.

Amid civil war, Turkish bands reach the Aegean; Nicaea itself becomes the Seljuk capital by 1081.

The young general seizes power amid collapse on every frontier and founds the century of the Komnenoi.

Alexios buys Venice's fleet against the Normans with sweeping trade privileges — the germ of Italian commercial dominance.

With Cuman allies Alexios annihilates the Pechenegs, ending decades of nomad pressure on the Balkans in one day.

Answering an appeal Alexios never quite made, the armies of the West mass before Constantinople en route to Jerusalem.

The city surrenders to Alexios' men during the crusader siege; western Anatolia returns to the empire.

The epic of the twice-born border lord takes shape — the great vernacular poem of the Anatolian frontier.

John II succeeds smoothly — a rarity — and continues the patient Komnenian restoration.

John II destroys the Pechenegs as a people; their remnant is settled as imperial soldiers.

John II and Eirene's triple church includes a 50-bed hospital with specialist wards — the most advanced of the age.

The youngest son of John II takes the throne; his reign carries Komnenian power and pageantry to their height.

In monastic retirement the porphyrogenita completes her history of her father — the masterwork of Byzantine historical literature by a woman's hand.

Manuel's army crushes Hungary; Dalmatia, Croatia and Sirmium pass under imperial control.

The Seljuks ambush Manuel's great army in a mountain pass; the last real attempt to retake the Anatolian plateau dies there.

The mob of Constantinople slaughters the city's western merchants as Andronikos Komnenos marches on the capital.

William II's Normans storm the second city with great slaughter; the outrage topples Andronikos I within weeks.

The last Komnenos is torn apart by the mob; the Angeloi preside over accelerating disintegration.

The revolt of the brothers Peter and Asen founds the Second Bulgarian Empire; the Balkan hegemony of 1018 is finished.

The Fourth Crusade storms and sacks the city — 'even the Saracens would have been more merciful,' wrote Choniates. The empire shatters.

Theodore Laskaris gathers the refugees at Nicaea; rival successor states rise at Trebizond and in Epiros.

Theodore I kills the Seljuk sultan in single combat, securing the Nicaean state's eastern flank.

Niketas Choniates, refugee of 1204, finishes the great account of the empire's fall — history written in grief.

Bulgaria destroys Epiros' bid for Constantinople, leaving Nicaea the sole credible Greek claimant.

Michael Palaiologos' generals defeat the coalition of Epiros, Achaia and Sicily — the door to Constantinople opens.

Alexios Strategopoulos slips into the city with 800 men while the Latin garrison is away; Michael VIII enters in triumph on 15 August.

Michael VIII accepts union with Rome to fend off Charles of Anjou; clergy and people bitterly reject it at home.

Sicily's revolt destroys Charles of Anjou's invasion; Michael VIII, who financed it, dies the same year — repudiated by his own church.

A destructive earthquake strikes Constantinople, wrecking houses, churches and stretches of the sea walls.

Osman defeats an imperial force near Nicomedia — the first dated victory of the dynasty that will end the empire.

Theodore Metochites finishes the mosaic and fresco cycles of the Chora church — the summit of Palaiologan art.

Bursa surrenders to Orhan after a decade of blockade and becomes the first Ottoman capital.

The city of councils and of the exile empire surrenders to Orhan; Nicomedia follows in 1337.

The regency of John V and John Kantakouzenos tear the empire apart for six years, hiring Serbs and Turks against each other.

Plague reaches Constantinople from Caffa — among the first cities of Europe struck — killing perhaps a third of its people.

A council in the Blachernai upholds Gregory Palamas and hesychast theology as Orthodox doctrine.

An earthquake throws down the walls of Gallipoli; Ottoman troops occupy the ruins at once — the first foothold in Europe.

The Ottomans destroy the Serbian lords of Macedonia at night on the Maritsa; the Balkans lie open.

Ottomans and Serbs bleed each other at Kosovo Polje; both rulers die, and Serbia passes into vassalage.

Bayezid annihilates the Franco-Hungarian crusade on the Danube; no help will come by land again.

Timur captures Bayezid and shatters the Ottoman state — a reprieve that buys Constantinople half a century.

George Gemistos Plethon teaches Platonic philosophy at Mistra; his students will carry Greek learning to Renaissance Italy.

The first full Ottoman siege of the capital is abandoned after a rebellion in Anatolia — the walls hold one last time.

Murad II storms the second city, held at the end by Venice; its fall forewarns of the capital's fate.

John VIII and Patriarch Joseph accept union with Rome in exchange for aid; at home the union is despised — 'better the turban than the tiara.'

Murad II destroys the last crusade at Varna; King Wladyslaw of Poland and Hungary is killed in the charge.

The last emperor is crowned at Mistra and sails to his capital of perhaps 50,000 souls.

Mehmed II raises the 'Throat-Cutter' fortress on the Bosphorus in four months, closing the straits to the city's relief.

After a 53-day siege Mehmed II's army storms the Theodosian Walls; Constantine XI dies fighting at the St Romanos gate, and the Roman Empire ends.