The Numantine War (from Bellum Numantinum in Appian’s Roman History) was the final battle of the Celtiberian Wars, fought by the Romans to control the people living near the Ebro River, now part of Spain. This war lasted 20 years and involved the Celtiberian tribes of Hispania Citerior and the Roman government. It began in 154 BC when the Celtiberians of Numantia, located on the Douro River, rebelled. The first part of the war ended in 151 BC, but fighting resumed in 143 BC with another uprising in Numantia.

This war happened at the same time as the Lusitanian War in Hispania Ulterior. The Lusitanians were defeated by Sulpicius Galba, who broke their surrender and killed their leaders. Meanwhile, the Arevaci of Hispania Citerior continued fighting and allied with the Lusitanian leader Viriathus.

When open war began again in 143 BC, Rome sent several generals to the Iberian Peninsula to deal with the Numantines. In 143 BC, Quintus Caecilius Metellus Macedonicus tried to capture Numantia through a siege but failed. However, he managed to subdue other tribes of the Arevaci. His successor, Quintus Pompeius, was unsuccessful and suffered heavy losses. He secretly negotiated a peace agreement with Numantia, following the previous treaty. But in 138 BC, a new general, Marcus Pompillius Laenas, arrived. When Numantine envoys came to complete their peace obligations, Pompeius denied negotiating any agreement. The Senate ruled that Pompeius’s peace deal was invalid and sent Gaius Hostilius Mancinus to continue the war in 136 BC. Mancinus attacked Numantia but was repeatedly defeated and forced to accept a treaty, negotiated by a young Tiberius Gracchus. The Senate refused to approve this treaty and instead sent Mancinus to Numantia as a prisoner. His successors, Lucius Furius Philus and Gaius Calpurnius Piso, avoided fighting the Numantines.

In 134 BC, the Roman general Scipio Aemilianus was sent to Hispania Citerior to end the war. He gathered 20,000 Roman soldiers and 40,000 allies, including Numidian cavalry and 12 war elephants under Jugurtha. Scipio built seven fortresses around Numantia before starting the siege. After suffering from disease and starvation, most surviving Numantines chose to commit suicide rather than surrender to Rome. The Roman victory over Numantia brought lasting peace to Hispania until the Sertorian War over 50 years later.

This war also marked the beginning of important careers. Tiberius Gracchus served as a quaestor during Mancinus’s failed siege. Because of his father’s good relationship with the Numantines, Tiberius was chosen to negotiate the treaty. Gaius Marius also fought in this war, as did Jugurtha, who later became a Roman enemy.