What was the greatest defeat by Roman Empire?

What was the greatest defeat by Roman Empire? 

1. The Battle of Allia (390BC)

A nearly forgotten battle of a forgotten war between the rising Roman Republic and the invading Gallic tribes under their Cheiftain Brennus.

The Battle was a Major is made notable because the Roman’s defeat led to the First Sacking of Rome. A humiliating defeat that humbled the Romans to near submission against both the Gauls and their Latin Allies.

But in this defeat helped the Romans rise from the ashes. Their military was improved. Abandoning phalanxes into something akin to the Legionairy system. Their Latin Allies who abandoned them in battle was brought to heel. And their rivalry against the Gallic tribes paved the way to hatred and near genocide that culminated to Julius Caesar conquering all of Gaul centuries later.

2. Battle of Carrhae

Crassus’s battle against the Parthian Army under Surena was a decisive and one sided affair for the Sassanids.

Though outnumbered, Surena was able to outmaneuver Crassus’s legions with the former’s all cavalry army made up of 90% horse archers and 10% Cataphracts.

The Romans, lacking both capable cavalry contingents and effective range weaponry (namely javelins) were no match against the rain of arrows and devastating armoured cataphract charges.

The Roman defeat sent shockwaves in the Empire. The loss of the legion led to Parthian Supremacy in the east while Crassus’s death brought the Roman Triumvirate to an end. Leading to the inevitable clash against the remaining two political parties under Caesar and Pompey that would pave the way to the fall of the Republic and the rise of the Roman Empire.

3. Battles of Teutoburg Forest

Hubris seems to be a common trend among Roman Defeats.

Nothing exemplifies this more than Quintus Varus’s defeat and the destruction of 3 whole legions in the Battles of Teutoburg Forest. I say Battles because the many clashes between the Romans and the Germanic Tribes along the forest and never as a full open battle.

This defeat stopped Roman expansion into Germania. Putting to a halt to Rome’s dreams of expanding beyond the Rhine and giving the Germanic Tribes breathing room to what soon would lead to the Great Tribal Migrations that would culminate in the fall of the Roman empire centuries later. Ctto