Notes — Anthony Kaldellis on the Roman Empire, Byzantium, and the Rise and Fall of Empires

Notes on Anthony Kaldellis in conversation with Lex Fridman — Lex Fridman Podcast (https://lexfridman.com/anthony-kaldellis), 30 June 2026.

Four questions [Adler frame]

Q1 — What is it about as a whole? Kaldellis, a historian of the Eastern Roman Empire, argues that the state conventionally labelled ‘Byzantine’ was never anything but the Roman Empire, continuing without rupture from 753 BC to 1453 AD. Across four hours he walks the whole 2,200-year arc — the kingdom, the republic, the imperial monarchy, the shift east to Constantinople, the fall of the western half, the near-death under the Persians and Arabs, the recoveries under Justinian and the Macedonian dynasty, and the final collapse — while making a structural argument underneath the narrative: the empire held together not because of any one emperor’s virtue but because of durable institutions (above all taxation and law) and a credible, tested bargain between rulers and subjects.

Q2 — How is it argued? Kaldellis argues from primary sources — legal codes, petitions, chronicles, letters — read against the grain of the ‘decline and fall’ tradition he thinks distorts the field. His method: pick a role that persists across centuries (a soldier’s oath, a woman’s legal standing, a taxpayer’s exemption) and ask whether it would still make sense to someone from another era; use hard statistics (46% of Constantinopolitan emperors deposed by violence, 120 civil wars in a thousand years) rather than impressions; and separate the state’s rhetoric (its ‘persona’) from what the evidence shows it actually did, following what he calls a Machiavellian discipline of judging actions over words.

Q3 — Is it true, in whole or part? The continuity thesis (Byzantium = Rome, not a successor state) is now close to scholarly consensus and is well supported here — legal, institutional, and self-identifying evidence is extensive. The claim that taxation, not religion or military dictatorship, is the empire’s load-bearing institution is Kaldellis’s own synthesis and clearly argued, though it is one historian’s weighting of causes among several plausible ones [?]. His downgrading of the sixth-century Plague of Justinian’s mortality (rejecting the 50% maximalist estimate) is presented as a live scholarly debate, not settled fact — he is explicit about this himself. His claim that iconoclasm mattered to at most a few hundred people is a strong, somewhat under-evidenced generalisation offered from his own reading of the sources [?]. The figure of 25,000 to 500,000 for Constantinople’s growth, and most numeric estimates throughout, are presented as orders of magnitude, not precise counts.

Q4 — What of it? For the wiki, this is the anchor source on Roman/Byzantine political history and gives the vault its first genuinely novel historiographical concepts in this field: the ‘monarchic republic’ model of imperial legitimacy, and the ‘long Roman Empire’ framing that replaces the conventional Byzantine/Roman split. Both merit their own concept pages. The episode also supplies the wiki’s first detailed treatment of two pivotal emperors, Constantine and Justinian, each substantial enough for a person page. The closing section, drawing explicit lessons for modern great-power politics (rhetoric must be credible, not just repeated; institutions built to outlast their builders), gives a secondary cross-wiki thread relevant to any future material on state legitimacy or institutional design.

Glossary

Long Roman Empire — Kaldellis’s term for the historiographical model that treats Roman history as one unbroken polity from 753 BC to 1453 AD, replacing the older convention of calling the eastern half after 476 AD (or after 330 AD) something separate — ‘the Byzantine Empire’ or ‘the Empire of the Greeks’. [§ The Roman Empire and the Byzantine Empire]

Monarchic republic — Kaldellis’s term for the East Roman state’s actual constitution: an executive monarchy (an emperor, basileus) operating within a polity still understood, in Roman terms, as a res publica — a commonwealth to be served, not owned. There was no hereditary right to the throne; legitimacy was earned and could be lost. [§ Why the Roman empire survived so long]

Edict of Caracalla (Constitutio Antoniniana, 212 AD) — the imperial edict extending Roman citizenship to nearly all free inhabitants of the empire, not merely a symbolic gesture: within a generation, provincials — including future emperors — held the empire’s highest offices. [§ Edict of Caracalla]

Crisis of the Third Century — roughly 235–284 AD; a concentrated run of civil wars (26 emperors in 50 years), hyperinflation, plague, and territorial fragmentation, ended by Aurelian’s reunification and Diocletian’s administrative reforms. [§ Crisis of the Third Century]

Tetrarchy — Diocletian’s system of four co-emperors (two senior ‘Augusti’, two junior ‘Caesars’) dividing the empire’s military burden without formally partitioning its territory; the mechanism by which Diocletian ended the Crisis of the Third Century. [§ Crisis of the Third Century]

Persona of the emperor — Kaldellis’s term for the consistent public image every emperor projected regardless of personal character: tireless, responsive to petitions, accountable, and acting solely for his subjects’ benefit — reinforced through law, court rhetoric, and public ceremony. [§ Power, violence, and civil war]

Perpetual referendum — Kaldellis’s description of how the Hippodrome and other mass gatherings (military musters, church congregations) functioned as an ongoing, informal test of an emperor’s standing — acclamation or booing in place of periodic elections. [§ Power, violence, and civil war]

Roman identity — the claim, defended at length, that ‘Roman’ remained a genuine, continuously-held political identity through the Greek-speaking, Christian centuries — not merely an antiquarian label historians retrofit onto medieval Constantinople.

Key claims by section

The Roman Empire and the Byzantine Empire [§ The Roman Empire and the Byzantine Empire]

‘Byzantine Empire’ is a later historians’ invention; the polity’s own subjects called it Romania and called themselves Romans throughout, without a break, down to 1453.
The rupture is a Western historiographical choice, not a fact of the sources: Western Europe wanted to disown the Greek-speaking, Christian continuation of Rome, so it renamed it — first ‘Empire of the Greeks’, later ‘Byzantine Empire’.
The Ship-of-Theseus analogy: every component of Roman society changed over 2,200 years, but the narrative thread — a continuously-recognised political community — never broke, unlike, say, Greek culture, which is not tied to a single state.

2,200 Years of Roman History [§ 2,200 Years of Roman History]

Three phases: the kingdom (to c. 510 BC), the republic (to 27 BC), and the imperial monarchy thereafter, itself split between a Rome-centred and a Constantinople-centred phase.
Most of the standard turning-point dates (395 AD East/West split, 476 AD fall of the West) mark the endpoint of a long gradual process, not a sudden rupture — a general point of historical method Kaldellis returns to repeatedly.
No single ‘Roman’ would have recognised every other Roman across the full span as obviously the same kind of person — the diversity within any one generation (a senator versus a slave’s son) is already large; continuity is a property of the political community’s story, not of shared lived experience.

Power, violence, and civil war [§ Power, violence, and civil war]

46% of Constantinopolitan emperors were deposed by violence; roughly 120 civil wars over the thousand years Kaldellis studies. Instability at the top was constant, but it rarely touched the lives of ordinary provincials.
The ‘persona’ the state projected — sleepless, accountable, responsive to petitions — was, in Kaldellis’s reading, generally sincere: the gap between rhetoric and action was small, because emperors were structurally incentivised to close it (no hereditary right to rule meant continuous, real accountability to the risk of rebellion).
The Hippodrome (and other assemblies — the army, the church, public fora) functioned as an informal, continuous test of the emperor’s popularity, closer to a ‘perpetual referendum’ than to fixed-term democratic elections.
Civil war, though costly, functioned as the actual check on power — the credible threat of overthrow disciplined behaviour more effectively than any modern institutional constraint.
The Eastern Roman Empire was not a military dictatorship in Kaldellis’s view: the army was almost never turned against the domestic population as an instrument of social control.

Edict of Caracalla [§ Edict of Caracalla]

Before 212 AD, at most a third of the empire’s free population held Roman citizenship; the rest held only local citizenship.
Caracalla’s edict extended citizenship to nearly all free inhabitants — and, unusually for any pre-modern empire, meant it: within a generation, all emperors and the most powerful officials came from the provinces.
Kaldellis contrasts this with the British Empire, which never extended equivalent metropolitan rights to colonial subjects — a genuine structural difference, not a matter of degree.
The edict helped ‘sap discontent’ during the subsequent Crisis of the Third Century by giving provincials a stake in the imperial system rather than a grievance against it.

Crisis of the Third Century [§ Crisis of the Third Century]

26 emperors murdered in roughly 50 years, hyperinflation, a plague (249–262 AD, possibly smallpox), and temporary territorial fragmentation (the breakaway ‘Empire of the Gauls’).
Even the breakaway regions had no alternative political model to a Roman one — separatist generals simply tried to build a rival Roman state rather than a genuinely different polity, evidence for how total the Roman political imagination had become.
Diocletian (284–305 AD) ended the crisis by expanding, not shrinking, government: the Tetrarchy (four co-emperors), universal taxation (ending Italy’s ancient tax exemption), and a full imperial census. Kaldellis reads the resulting labour restrictions (soldiers’ sons, tax-bound farmers) as tax-enforcement mechanisms, not evidence of a rigid caste system — social and physical mobility remained considerable.

Constantine and the new Roman Empire [§ Constantine and the new Roman Empire]

Constantine, from within Diocletian’s system, won a series of civil wars to become sole emperor by 324 AD and founded Constantinople on the site of Byzantium in 330 AD, explicitly as a ‘New Rome’ — the most successful of several such ‘copy-and-paste Romes’ emperors had been founding since Rome ceased to be their working capital.
Constantinople’s geography — midway between the Danube and Euphrates frontiers, at the hinge between Europe and Asia — let the state respond to threats from either side and stopped the empire’s recurring tendency to split at the Bosporus during civil wars (the fracture point later moved west, to the Adriatic).
Kaldellis ranks Constantine as his single most consequential emperor (not most admirable — he had his son Crispus and his wife executed without explanation) purely on the scale of irreversible, largely beneficial decisions: founding Constantinople and steering the empire toward Christianity.
Constantinople’s population grew from roughly 20,000–25,000 to half a million within two centuries almost entirely through immigration — driven by the forced relocation of c. 2,500 senatorial households (each with large staffs) and a grain dole extended to up to 200,000 residents, itself diverted from Rome’s own supply.

Christianity in the Roman Empire [§ Christianity in the Roman Empire]

Kaldellis frames the relationship as Rome co-opting Christianity rather than Christianity triumphing over Rome: the faith had no independent state-building history (unlike Islam, which built its own state from scratch) and instead grew inside, and was absorbed by, a fully-formed Roman imperial system.
Christians were perhaps 10% of the population at Constantine’s conversion (312 AD, after the Battle of the Milvian Bridge) and not politically powerful; Kaldellis rejects the cynical-convenience theory of the conversion for lack of a plausible payoff, and instead reads it as a genuine, if pragmatically expressed, belief.
Full Christianisation was a five-century process (majority status arguably not reached until the fifth century, ‘solid’ Christian society not until the sixth), driven by incentives (church charity, land endowments) and disincentives (escalating legal restriction of traditional religious practice).
Because Christianity makes exclusive truth claims, it was simultaneously more unifying (a shared, powerful identity) and more polarising (heresy, schism) than the religions it displaced — a paradox Kaldellis declines to resolve one way or the other.

Fall of the Western Roman Empire [§ Fall of the Western Roman Empire]

The core mechanism: once the western state failed to defeat or absorb an invading army and lost a province’s tax revenue (as with the Vandals in North Africa), it could no longer fund the forces needed to repel the next incursion — a self-reinforcing spiral.
Geography partly explains the East/West divergence: without a fleet, the Goths who crossed the Danube in 376 AD could not reach Asia Minor and were pushed instead toward Italy — richer, more accessible, and undefended by sea.
Roman law as it survives today is substantially the East’s law, not Rome’s: Constantinople was already codifying law for the West by the 430s, and Justinian’s sixth-century recodification (the Corpus Juris Civilis) became the basis of most later Western civil-law systems.
Kaldellis frames this not as Western collapse followed by a new Byzantine state, but as the centre of a single continuing Roman polity shifting east — the West’s decline is a consequence of that shift, not an independent event.

Eunuchs, Taxes, and Power [§ Eunuchs, Taxes, and Power]

Civilian government’s central task was funding the military (the largest budget item) through census, taxation, and a large legal-administrative apparatus; taxation is, in Kaldellis’s own words, ‘the heart of it’ — the single factor he would point to if asked for one explanation of how the society worked.
No isolated, tax-unaware peasant communities existed, in Kaldellis’s assessment — every parcel of arable land was censused for centuries, taxes were collected roughly three times a year in cash, kind, and services, and even the remotest hermits are described in sources by reference to how far they’d gone to escape the tax census.
Eunuchs staffed the imperial household and were deliberately given power (sometimes military commands) precisely because they had no family networks of their own and so depended entirely on the emperor — a counterweight against being displaced by hereditary aristocratic or bureaucratic networks.
Tax exemptions, granted individually by petition rather than through a fixed code, tended to accumulate and obscure the system over time — a dynamic Kaldellis compares directly to the growth of modern tax codes.

Emperor Justinian and wars of conquest [§ Emperor Justinian and wars of conquest]

Justinian (r. 527–565 AD), from a poor Balkan family, codified Roman law (the Corpus Juris Civilis, largely the work of the jurist Tribonian), married the former performer Theodora, and reconquered North Africa and, at great and unsustainable cost, Italy and southern Spain.
Kaldellis judges conquest itself no automatic mark of greatness: Justinian stripped the eastern frontier of troops to fund the western wars, leaving Antioch exposed to Persian sack, and left successors an overstretched, under-defended empire.
Also responsible for the brutal suppression of the Nika riots (532 AD, over 30,000 dead) and the subsequent rebuilding of Hagia Sophia — Kaldellis frames Justinian as genuinely double-edged, unable to be placed cleanly on either his best- or worst-emperor lists.
Kaldellis argues for a moderate, not maximalist, reading of the Plague of Justinian (541 AD onward): narrative sources show no pause in Justinian’s multi-front wars or in tax collection, which he thinks is inconsistent with a 50% mortality event.

The Arab conquests [§ The Arab conquests]

The 602–628 AD Roman-Persian war (triggered by Heraclius’s own civil war against Phocas) mutually exhausted both empires just before the Arab conquests of the 630s–640s, which Kaldellis treats as close to overdetermined: two war-shattered, undefended-from-Arabia states meeting a newly unified, motivated army.
Loss of Egypt ended Constantinople’s grain supply and caused sustained population decline; recovery took decades of defensive consolidation in Asia Minor, culminating in Greek fire (a closely-guarded incendiary weapon, deployed by ship-mounted siphon and hand-thrown grenade) and the successful defence of Constantinople against two Arab sieges (674–678 AD and 717–718 AD).
Iconoclasm (removal of religious images, eighth–ninth centuries) is, in Kaldellis’s reading, a controversy of a few hundred elite clergy and emperors, not a popular movement — a caution about letting the concerns of the literate minority who wrote the sources stand in for the concerns of society as a whole.

Why the Roman empire survived so long [§ Why the Roman empire survived so long]

Kaldellis reframes the empire’s history away from a repeating ‘oscillation’ and toward a pattern of brief, exogenous crises (foreign invasion) interrupting long, endogenous stretches of consolidation and regrowth — and argues historians should define the society by the endogenous recovery, not the crises.
No internal separatist movement, tax-collection collapse, elite partition, or successful peasant uprising occurs anywhere in the empire’s history except Bulgaria’s secession (fully achieved only in 1185, after roughly two centuries of intermittent rebellion) — the structural markers of state failure are essentially absent until the very end.
Two-part explanation for cohesion: (1) authorities made a sustained, and largely sincere, effort to persuade subjects they ruled on their behalf; (2) a tightly unified Roman and Orthodox identity, held against neighbours who were neither.
The ‘monarchic republic’ framing: emperors held executive, monarchical power but operated within a polity still conceived, in the Roman sense, as a res publica to be served — a structural difference from purely dynastic empires that never emerged from a republic.
The final decline is dated to the 1300s–1340s: loss of Asia Minor (c. 1300) removed one of the empire’s two territorial ‘wings’, after which civil wars and Serbian expansion removed the last strategic slack; 1453 (the fall of Constantinople) came over a century later, delayed in part by Timur’s unrelated defeat of the Ottomans around 1400.

Lessons from history [§ Lessons from history]

Kaldellis’s central lesson for modern great powers: institutions that visibly work for the benefit of the ruled — and are credibly explained as such — serve the ruling class’s own long-term interest, even at short-term cost.
Rhetoric that is not backed by matching action is not merely wasted — it corrodes legitimacy over time; Kaldellis contrasts the East Roman state’s generally credible persona with what he sees as a wide rhetoric-action gap in modern American foreign policy.
Closing reflection: Kaldellis identifies only three qualitatively distinct phases of human history so far (hunter-gatherer, agricultural, industrial/technological) and expresses cautious optimism about the present despite serious open risks.