Publius Popillius Laenas was consul in 132 BC, and builder of the Via Popilia.
When consul he incurred the hatred of the populares by his harsh measures as head of a special commission appointed to take measures against the accomplices of Tiberius Gracchus.
In 123 BC Gaius Gracchus brought in a bill prohibiting all such commissions, and declared that, in accordance with the old laws of appeal, a magistrate who pronounced sentence of death against a Roman citizen, without the people's assent, should be guilty of high treason.
It is not known whether the bill contained a retrospective clause against Laenas, but he left Rome and sentence of banishment from Italy was pronounced against him.
[1] The name of the town of Forlimpopoli is probably related to Publius Popillius Laenas who might have founded it during his time as consul.