As the plans to attack the Arevaci was formulated, Arganthonios Culchid, the man in charge of handling the ports, bought himself the leadership. But as his first year as ruler was going to its end he died of natural causes at which point Caisaros restored his rule. In the end of that year war with the Arevaci finally started. The Arevaci could count on the support of the Cantabri, the Lusitani and the Carpetani, while the Edetani fought on the Ilergetan side.
The initial fights against the Arevaci outside Numantia quickly led to victory. However while the Arevaci caused little trouble in the war for the Ilergetans (the Edetani on the other hand had their hands full with the Arevaci forces in the south), their Carpetani and Cantabri allies caused much headache for the Ilergetans.
In the end Numantia was taken, and since the Edetani had been overrun, and the Cantabri and Carpetani moved in and taken a fair number of Ilergetan towns, a white peace was signed. Shortly after the peace, the Arevaci wanted economic help, which was denied, so after five years of peace, the Arevaci felt that they should try to resume hostilities. The war was formally initiated by the Ilergetans after Chiomara, Caisaros' sister, had been brutally murdered by the Arevaci. But this war didn't end up well for the Arevaci, outside Numantia an Arevaci army numbering 9,000 was annihilated, and after some additional fighting the Arevaci ceded Vascones, however their allies decided to remain at war.
The Cantabri were soon beaten (although with losses) and their strongholds put under siege. However the Carpetani warriors, led by Cesarus laid siege to Ilerda, and smashed the Ilergetan forces sent to raise the siege into pieces.
However the Cantabri soon was forced to pay tribute, and Arganthonios Carosid then led the Ilergetan warriors to victory over the Carpetani.
They soon paid a massive tribute to the Ilergetans, and the Lusitani, who had raided coast had been beaten and accepted a simple peace. Now the republic was at peace again, however manpower was exhausted, and worrying news came that the Carthaginians had taken control of Contestani, and were strengthening their hold over southern Iberia.
However the Ilergetes had hardly recovered from the previous wars when the Arevaci attacked. While neither side called their allies (the Arevaci allies all still had treaties with the Ilergetans, while the Edetani had hardly any military at all), it proved to be a hard war for the Ilergetes. The Arevaci leader Rhetogenes led a vast host into Lusones, the Ilergetes faced him, and while they could claim victory, it was a costly one.
Regardless Arganthonios quickly pursued the Arevaci in a hope to smash their army and crush them once and for all. It didn't end well. Arevaci warriors ambushed the Ilergetans and only a few Ilergetan warriors survived.
With no manpower and no armies, the Ilergetans tried to hire mercenaries to counter the threat, and while the Arevaci was not defeated in battle and managed to occupy many towns, an army of Gallic warriors managed to reach and seize Numantia, convincing the Arevaci to sign a white peace. Now while the Ilergetan Republic was at peace again, with only a few warriors left alive, and no manpower to replace them with, was forced to hire mercenaries mainly so that some sort of army could be had, in case war came again.