The Praetorian Guard — the bodyguard that sold the throne was abolished by the man it fought

The Praetorian Guard — the household troops created by the emperor Augustus around 27 BC to protect the person of the Roman ruler — became over three centuries the most dangerous force in Roman politics, and it was permanently abolished by the emperor Constantine in 312 after it had fought against him. On 28 October 312, Constantine defeated his rival Maxentius at the Battle of the Milvian Bridge outside Rome; Maxentius drowned in the Tiber, and the Praetorians who had made him emperor and died for him on the riverbank were the corps’ last stand. Constantine disbanded the survivors, scattered them to the frontiers, and demolished their great fortress, the Castra Praetoria, ending a body that had lasted some three hundred and thirty-nine years.

What fell was the original imperial bodyguard, and the institution that had turned guarding the emperor into the power to choose, depose, and even kill him. Augustus established the Guard as nine cohorts of elite soldiers, the only substantial armed force permitted near Rome, better paid and shorter-served than the legions. Concentrated by Tiberius into a single fortified camp on the edge of the city in 26 AD, the Praetorians acquired what no other unit possessed: a permanent armed presence at the center of power, alongside an emperor with no comparable force to balance them.

From that position the Guard learned that the men they protected served at their sufferance. They assassinated Caligula in 41 AD and installed Claudius; they intervened repeatedly in the succession; and in 193 AD, having murdered the emperor Pertinax, they put the empire up for auction and sold it to the highest bidder, Didius Julianus. They were a praetorian corps in the literal and the figurative sense — a bodyguard that had become a kingmaker, repeatedly trading their loyalty for donatives and treating the throne as a prize in their gift.

The mechanism of the fall was the corps backing the losing side in a civil war fought by an emperor strong enough to dispense with them. When the tetrarchic system fractured, the Praetorians in Rome proclaimed Maxentius and fought for him to the end. Constantine, commanding a battle-hardened field army of his own and owing the Guard nothing, beat that army at the Milvian Bridge and then abolished the corps outright rather than buy its loyalty as so many predecessors had. The reforms of the era had already made the old Guard militarily redundant; Constantine’s victory made its destruction final.

The Streltsy — Russia’s musketeer caste, broken by Peter the Great’s terror

The Streltsy — Russia’s first standing infantry, founded by Ivan the Terrible around 1550 — were a hereditary corps of musketeers who became a turbulent armed caste at the heart of Muscovite politics, and they were broken by Peter the Great after their revolt in 1698. When the Moscow regiments mutinied while the young tsar was traveling in Western Europe, Peter rushed home, crushed the survivors of the corps with a campaign of mass torture and execution, and dissolved the Moscow Streltsy. Between September 1698 and February 1699, roughly 1,182 Streltsy were put to death and hundreds more flogged, branded, or exiled; further investigation and killing continued for years, and the corps was wound down over the following two decades.

What fell was not merely a regiment but a political institution. Created in the mid-sixteenth century as Russia’s first permanent infantry armed with firearms — the arquebus and later the musket — the Streltsy filled the bulk of the army for a century. Over time their service became lifelong and then hereditary; they lived in their own Moscow settlements, drew state pay in money and grain, and supplemented it with trade and craft. By the late seventeenth century, numbering tens of thousands, they had become a praetorian element: an armed bloc that could intervene in succession disputes and make or unmake regents.

They had already shown that power. In the Moscow uprising of 1682 the Streltsy stormed the Kremlin, killed leading boyars, and helped install Peter’s half-sister Sophia Alekseyevna as regent — a trauma the boy Peter witnessed directly and never forgot. Their grievances were real: arrears of pay, abuses by commanders, and resentment of Peter’s foreign-styled new regiments and his hostility to their privileges and their conservative, Old Believer sympathies.

The mechanism of the fall was a failed revolt answered with calculated terror. In 1698, with Peter abroad on his Grand Embassy, Moscow Streltsy regiments mutinied and marched on the capital, some hoping to restore Sophia to power. Loyal troops under the foreign general Patrick Gordon and the boyar Aleksei Shein crushed them at the New Jerusalem Monastery west of Moscow on 18 June 1698. Peter returned in fury, reopened the investigation under savage torture, and turned the punishment into a public spectacle designed to annihilate the corps as a force in Russian politics forever.