Romulus drew out his troops into Campus Martius, or field of Mars, just beneath the Capitol, or great fort on the Saturnian Hill, and marched against the Sabines; but while he was absent, Tarpeia, the daughter of the governor of the little fort he had left on the Saturnian Hill, promised to let the Sabines in on condition they would give her what they wore on their left arms, meaning their bracelets; but they hated her treason even while they took advantage of it, and no sooner were they within the gate than they pelted her with their heavy shields, which they wore on their left arms, and killed her.

The cliff on the top of which she died is still called the Tarpeian rock, and criminals were executed by being thrown from the top of it.

Romulus tried to regain the Capitol, but the Sabines rolled down stones on the Romans, and he was stunned by one that struck him on the head; and though he quickly recovered and rallied his men, the battle was going against him, when all the Sabine women, who had been nearly two years Roman wives, came rushing out, with their little children in their arms and their hair flying, begging their fathers and husbands not to kill one another.

This led to the making of a peace, and it was agreed that the Sabines and Romans should make but one nation, and that Romulus and Tatius should reign together at Rome.

Romulus lived on the Palatine Hill, Tatius on the Tarpeian, and the valley between was called the Forum, and was the market-place, and also the spot where all public assemblies were held.