The Timpson Lyceum · History of Rome – Titus Livius (2025)

Early Roman Republic – Lecture 10 (History of Rome)

Overview

With the expulsion of Tarquinius Superbus in 509 BC, Rome abolished the monarchy and improvised the institutions of the Republic — a government designed above all to prevent any one man from again holding a king's power. The kingship was split between two annually elected consuls, the sacred duties of the old king were parked in a subordinate rex sacrorum, and the whole citizenry swore a binding oath never again to tolerate a king. This lecture traces the fragile first years of that experiment: the founding consulship of Brutus and Collatinus, the forced resignation of Collatinus for the crime of bearing the Tarquin name, and the deadly Tarquin conspiracy in which Brutus condemned his own sons.

The exiled Tarquin did not go quietly. He tried three times to claw his way back — first by conspiracy inside the walls, then with the Etruscan armies of Veii and Tarquinii at the Battle of Silva Arsia, and finally by enlisting Lars Porsenna of Clusium, the greatest lord in Etruria. Porsenna's campaign produced the founding legends of Roman virtus: Horatius Cocles holding the Pons Sublicius single-handed, Gaius Mucius Scaevola thrusting his hand into the fire, and Cloelia swimming the Tiber to freedom. Whether history or patriotic myth, these stories encode how a small, determined citizen-state survived encirclement — and they set the template for the Roman self-image for the next five centuries.

Key Concepts

• Fall of the monarchy (509 BC) — After the rape of Lucretia and the tyranny of Tarquinius Superbus, the Tarquins were driven out. Rome would remain a monarchy in living memory only: it had been ruled by kings for roughly two and a half centuries (from the traditional founding in 753 BC), longer than the whole span the story is being told against.
• The two consuls — The king's civil and military power (imperium) was divided between two magistrates elected for one year, each able to check the other. The first pair were Lucius Junius Brutus and Lucius Tarquinius Collatinus (Lucretia's widower).
• Fasces and lictors — A bundle of rods (for beating citizens) tied around an axe (for executing enemies), carried by 12 lictors who served as each consul's enforcers. The consuls alternated holding the fasces month by month to show who currently commanded; Brutus, having polled highest, held them first.
• Rex sacrorum — The king's religious functions were preserved in a priest, the "king of sacred rites," deliberately made subordinate to the Pontifex Maximus so that no residue of royal authority could grow dangerous.
• The oath against kingship — While emotions ran high, the whole people swore never to suffer a king in Rome again. Brutus refilled the Senate to 300 members, replacing those Tarquin had killed off or let lapse.
• Resignation of Collatinus — Distrusted merely for the hated name Tarquinius, Collatinus was persuaded by Brutus to resign and leave for Lavinium. Publius Valerius (later Publicola) replaced him.
• The Tarquin conspiracy — Tarquin's envoys, ostensibly reclaiming his property, secretly recruited disaffected young nobles to open the city gates. A slave overheard the plot and produced the incriminating letters. Among the conspirators were Brutus's own two sons, whom he condemned to death; the informing slave was freed, made a citizen, and rewarded.
• Battle of Silva Arsia (509 BC) — Tarquin's Etruscan allies from Veii and Tarquinii fought Rome to a bloody draw; Brutus and Tarquin's son Arruns killed each other in the opening cavalry clash. By tradition the god of the Arsian wood proclaimed at night that the Etruscans had lost by one man. Publicola celebrated a triumph; Rome observed a year of mourning for Brutus, "father of the Republic."
• Publicola's laws — To quiet suspicion that he sought tyranny, Valerius earned the name Publicola ("friend of the people") by (1) making it lawful to kill anyone who tried to make himself king, and (2) granting the assembly the right of appeal (provocatio) — a veto over a magistrate's sentence. He also lowered the fasces before the assembly, symbolizing that the people outrank any magistrate.
• Lars Porsenna of Clusium — The most powerful Etruscan king, "the Athens of Etruria." Rome prepared for his siege by stockpiling grain, nationalizing the salt works, and taxing only the very wealthy — winning the plebs' loyalty by making the rich bear the war's cost.
• Horatius Cocles — Held the far end of the Pons Sublicius (Rome's wooden bridge) against Porsenna's whole army while the Romans demolished the span behind him, then swam the Tiber in armor. Rewarded with as much land as he could plow in a day.
• Gaius Mucius Scaevola — Slipped into the Etruscan camp to assassinate Porsenna, killed the wrong man, and — to prove Roman resolve — thrust his right hand into the altar fire, earning the name Scaevola ("left-handed"). His claim that 300 more youths had sworn to try helped push Porsenna to terms.
• Cloelia — A hostage girl who led a band of maidens in escape across the Tiber. Sent back under the treaty, she so impressed Porsenna with Roman good faith that he freed her and half the hostages. Peace cost Rome the land north of the Tiber and a delivery of hostages.

Worked Example

Why one man could hold a bridge against an army — the chokepoint arithmetic of the Pons Sublicius. The puzzle is identical to Thermopylae: how can a handful stop thousands? The answer is that terrain, not courage alone, sets how many can fight at once.

1. Frontage caps the fight. The Pons Sublicius was a narrow timber bridge admitting only a few men abreast. Let the fightable frontage be $w = 3$. No matter how large the Etruscan army $N$, only $w$ attackers can reach the defenders at any instant. Horatius plus two comrades ($d = 3$) exactly matched that frontage, so the local force ratio was

$\frac{w}{d} = \frac{3}{3} = 1,$

an even fight — even though the army-wide ratio against Rome's covering party was hopelessly lopsided.

1. Numbers are wasted. With $N \approx 10{,}000$ Etruscans but only $w = 3$ engaged, the fraction of the army that could act at once was

$\frac{w}{N} = \frac{3}{10{,}000} = 0.03\%.$

The other $9{,}997$ men stood idle behind their own front rank. Numerical superiority was neutralized by geometry.

1. The clock that mattered was the demolition, not the killing. Victory required only that the defenders survive long enough to cut the bridge. Suppose the work party needs $T = 20$ minutes to sever the far span, and each attacker in a frontage slot is beaten back or falls roughly every $\tau = 20$ seconds. Then the number of attackers who can even reach the defenders in that window is

$w \cdot \frac{T}{\tau} = 3 \cdot \frac{20 \times 60}{20} = 3 \cdot 60 = 180.$

1. Compare the pools. Facing at most $180$ sequential opponents — three at a time — is survivable for a champion; facing $10{,}000$ at once is not. The chokepoint converted an impossible $10{,}000$-vs-$3$ problem into a manageable $180$-vs-$3$ endurance test.

2. The decisive moment. When the span dropped, the "engageable" frontage fell from $w = 3$ to $w = 0$: the army could no longer bring any force to bear, and Horatius had only to reach the water. The lesson in numbers is that a defender should force battle where frontage $w$ is small, making holding time independent of the enemy's total strength $N$. $\blacksquare$

Summary

• The Republic (509 BC) split the king's power between two annual consuls, subordinated the king's priestly role to a rex sacrorum, and bound the people by oath never to accept a king again.
• Brutus and Collatinus were the first consuls; Collatinus resigned over his Tarquin name, and Brutus executed his own sons for joining the Tarquin conspiracy before dying at Silva Arsia.
• Publicola secured the young state with laws permitting the killing of would-be kings and granting the people the right of appeal (provocatio).
• Against Lars Porsenna, Rome's survival was framed as a triumph of virtus — Horatius Cocles at the bridge, Mucius Scaevola at the fire, and Cloelia in the river.
• The bridge episode captures the era's core military logic: a narrow chokepoint negates numerical superiority, letting a few hold off an army long enough to change the strategic situation.