Why did Romulus kill Remus?

A quarrel over birds

The twins had been thrown into the Tiber as babies, nursed by a she-wolf and raised by a herdsman. Grown up, they decided to build a city at the place where they had been saved. But twins have no elder to settle who rules, so they asked the gods. Each watched the sky from his own hill. Remus, on the Aventine, saw six vultures first. Romulus, on the Palatine, then saw twelve. One side claimed the kingship for being first, the other for having twice the birds (Livy 1.6–7). Plutarch adds that some said Romulus lied about his twelve until they actually appeared (Romulus 9).

Here Livy offers two endings. In the first, the argument turns into a fight, and Remus is struck down in the crowd. In the second, which he calls the more common story, Remus mocks his brother by jumping over the new walls, and Romulus kills him in a rage, vowing the same end for anyone else who leaps his walls.

Why a jump could be a crime

To a Roman, a city wall was not just stones. Plutarch says Romulus marked the city’s line with a plow, lifting the blade where the gates would be (Romulus 11). That line was holy. In his Roman Questions (27), Plutarch asks why Romans treated walls as sacred but not gates, and points to Remus, killed for leaping across a holy place.

The jump was also an insult. A wall that a man can hop over will not stop an army, and Remus was showing everyone that his brother’s city was a joke. In the story, Romulus answers with the first law his city ever has: its walls are not to be crossed.

Some Romans blamed another man

Plutarch reports that some said the killer was not Romulus but a follower named Celer, who then fled to Etruria; from him, he says, Romans called swift runners celeres (Romulus 10). The poet Ovid tells it that way too, with Celer striking the blow and Romulus holding back his tears at the funeral (Fasti 4.837–856). Dionysius of Halicarnassus writes that Romulus was so stricken by the death that he wanted to die himself (Roman Antiquities 1.87). Ovid even ties a festival to the murdered twin: the Lemuria, when Romans in May drove away restless ghosts, was once the Remuria, after Remus (Fasti 5.451–484).

A city that began with a brother’s blood

Romans of the civil wars read the story as a curse. Horace wrote that a bitter fate had driven the Romans ever since innocent Remus’s blood ran into the ground (Epodes 7). The poet Lucan said the first walls of Rome were wet with a brother’s blood (Civil War 1.95). Augustine, around 420, set Romulus beside Cain, who killed his brother Abel and then built the first city in the Bible (Genesis 4:17). Two cities, he wrote, founded on the same crime (City of God 15.5). Cain’s side of that story is in why Cain killed Abel.

Did it happen, and why Romulus’s name?

No. The twins belong to legend; the archaeology of early Rome is in how Rome was founded. Livy says the city simply took the name of its founder, but Plutarch already listed other theories, including a Trojan woman called Rhome (Romulus 1). Many historians think the name Roma came first and the founder was invented to explain it. T. P. Wiseman has argued that Remus joined the story later still, perhaps around 300 BC. The name came full circle: the last emperor in the West, deposed in 476, was a boy called Romulus.