Numantine War participant Arevaci
The first war was fought contemporaneously with the Lusitanian War in Hispania Ulterior. The Lusitanians were subdued by Sulpicius Galba, who betrayed their surrender and executed their leading men, and the Arevaci of Hispania Citerior continued the war and allied with the Lusitanian leader Viriathus.
After open war reignited in 143, Rome sent a series of generals to the Iberian peninsula to deal with the Numantines. In that year, Quintus Caecilius Metellus Macedonicus tried and failed to take Numantia by siege, but subjugated all the other tribes of the Arevaci. His successor, Quintus Pompeius, was inept and suffered severe defeats at their hands, so he secretly negotiated a peace with the city abiding by the previous treaty. Yet in 138 BC a new general arrived, Marcus Pompillius Laenas, and when the Numantine envoys came to finish their obligations of the peace treaty, Pompeius disavowed negotiating any such peace. The matter was referred to the Senate for a judgment. Rome decided to ignore Pompeius' peace and sent Gaius Hostilius Mancinus to continue the war in 136 BC. He assaulted the city and was repulsed several times before being routed and encircled, and so forced to accept a treaty, negotiated by a young Tiberius Gracchus. The Senate did not ratify this treaty either but only sent Mancinus to the Numantines as a prisoner. His successors Lucius Furius Philus and Gaius Calpurnius Piso avoided conflict with the Numantines.