Flags of the Roman Empire

Fall of Constantinople

Who & why: Sultan Mehmed II's Ottoman forces breach Constantinople's ancient land walls on 29 May 1453 after a seven-week siege, using massive siege cannon against defenses that had held for over a thousand years; Emperor Constantine XI Palaiologos dies fighting in the breach. This ends the Roman state for good, nearly 2,206 years after its traditional founding, and Constantinople becomes the Ottoman capital.

What it represents: the closing point of this page's arc. The Ottoman Empire that succeeds Byzantium in this same capital city is covered on its own page in this atlas.

Byzantine Empire (Eastern Roman continuation)

Who & why: Constantine the Great founds Constantinople on the site of Byzantium in 330 CE as a new eastern capital; after the West's fall in 476, the Eastern Empire endures, calling itself simply "Roman" throughout. Justinian I (527–565) briefly reconquers Italy, North Africa, and part of Spain and codifies Roman law; the empire survives crusader occupation (1204–1261), slow territorial loss, and repeated sieges before finally falling in 1453 — nearly a thousand years after the West.

What it represents: the double-headed eagle, looking both east and west, becomes the empire's definitive dynastic emblem under the Palaiologos dynasty (from the 13th century), evolving from the single-headed Roman aquila — shown here as an informed reconstruction of its later, most iconic imperial form.

Permanent East/West split & the West's fall

Who & why: Emperor Theodosius I dies in 395 CE and divides the empire between his two sons for good — earlier splits under Diocletian's Tetrarchy had been administrative, but this one never reunifies. The Western Roman Empire, weakened by repeated barbarian incursions, sees Rome itself sacked twice (410 by the Visigoths, 455 by the Vandals) before the Germanic general Odoacer deposes the last western emperor, Romulus Augustulus, in 476 CE — the conventional end date for "the fall of Rome."

What it represents: both halves continue to use Roman legionary and imperial symbolism, but they now answer to separate courts and separate fates — the West dissolving into Germanic successor kingdoms, the East persisting as what later historians call Byzantium.

Crisis, Tetrarchy & Constantine's Christian turn

Who & why: after the near-collapse of the Crisis of the Third Century (military anarchy, civil wars, economic breakdown), Diocletian restores order from 284 CE and splits administration into a four-ruler Tetrarchy to manage the empire's unwieldy size. Constantine the Great reunifies sole rule by 324, founds Constantinople as a new capital in 330, and, after his own conversion, sets Christianity on the path to becoming the empire's dominant faith — formalized as the state religion under Theodosius I in 380.

What it represents: the labarum, a military standard bearing the Chi-Rho Christogram, is adopted by Constantine after his reported vision before the Battle of the Milvian Bridge (312 CE) — the first explicitly Christian imperial symbol, replacing the old pagan legionary standards. Shown here as a reconstruction.

Roman Empire (Principate)

Who & why: Octavian, having defeated Mark Antony and Cleopatra at Actium (31 BCE), is granted the title Augustus by the Senate in 27 BCE, formally ending the Republic while preserving its institutions as a facade — the beginning of one-man imperial rule. Rome reaches its greatest territorial extent under Trajan (117 CE), spanning from Britain to Mesopotamia, before the mid-3rd-century Crisis brings the empire to the edge of collapse.

What it represents: the aquila (eagle) standard, carried by every legion since Marius's reforms (104 BCE), remains Rome's defining military and imperial emblem straight through the transition from Republic to Empire, still marked with the old Republican motto SPQR (Senatus Populusque Romanus — the Senate and People of Rome).

Roman Republic

Who & why: tradition holds that the last king, Tarquin the Proud, is overthrown in 509 BCE, replaced by a republic governed by elected magistrates and the Senate. Rome expands from a single city-state to control the entire Italian peninsula, then the wider Mediterranean through the Punic Wars against Carthage (264–146 BCE) and conquests in Gaul, Greece, and the East — while internal political strain, culminating in Julius Caesar's dictatorship and assassination (44 BCE) and the civil wars that follow, brings the Republic itself to an end.

What it represents: SPQR (Senatus Populusque Romanus) is the Republic's defining formula, stamped on standards, monuments, and later even manhole covers — a claim that sovereignty rests jointly with the Senate and the Roman people, carried by the vexillum banners of the legions.

Roman Kingdom

Who & why: Roman tradition dates the city's founding to 753 BCE, by Romulus (who becomes its first king after killing his twin brother Remus in the founding myth). Seven kings rule in the traditional account, ending with the tyrannical Tarquin the Proud, whose overthrow in 509 BCE establishes the Republic. Much of this era is legendary rather than securely documented history, though archaeology confirms a genuine early settlement on the site.

What it represents: no flag or fixed banner is attested from this earliest, semi-legendary period — shown here honestly blank rather than inventing one, consistent with this atlas's treatment of other pre-heraldic eras.

Iron Age Latium (pre-urban settlement)

Who & why: archaeology confirms genuine Iron Age hut settlements — postholes, hearths, and cremation burials of the Latial culture — on the Palatine Hill and its neighbors from around 1000 BCE, several generations before Rome's traditional 753 BCE founding date. These separate hilltop villages, inhabited by Latin-speaking Italic peoples, gradually coalesce into a single larger settlement over the 8th century BCE, a real process that the later legend of Romulus and Remus compresses into a single founding moment.

What it represents: no flag, banner, or even securely attested individual ruler survives from this pre-urban, pre-literate period — shown here honestly blank, consistent with this atlas's treatment of other pre-heraldic eras.

World context: this span overlaps the aftermath of the Late Bronze Age Collapse (c. 1200 BCE) that toppled the Mycenaean palaces and the Hittite Empire, the Phoenician colonization of the Mediterranean that traditionally founds Carthage in 814 BCE, and the Greek world's own emergence from its "Dark Age" into the age of Homer and the first recorded Olympic Games in 776 BCE — a wider Mediterranean Iron Age awakening of which the future Rome's hut villages were, at this stage, a minor and undistinguished part.