The war was carried on with varying fortunes for four years. In 141 B.C. it seemed to have been brought to a conclusion highly favourable to the Lusitanians and their gallant leaders. Viriathus surprised a Roman army that was investing one of the Lusitanian towns, and inflicted upon it so heavy a loss that it was compelled to raise the siege. In their retreat the Romans became entangled in a narrow pass, and were compelled to surrender. Viriathus was moderate in his demands. Lusitania was to be independent, and its people recognised as allies and friends of Rome. This treaty was ratified at Rome. But the ambition of a Roman general and the bad faith of the Senate brought this arrangement to an end. Servilius Cæpio was disappointed to find that the war had been brought to an end, and obtained permission from the Senate, which had not the effrontery to cancel the treaty, to make private war upon Viriathus. Before long something happened that gave the desired pretext, and Viriathus was declared a public enemy. He sent envoys to the Roman camp to arrange, if it were possible, terms of peace. Cæpio persuaded them by promises of great rewards to murder their chief. This they did, stabbing him in the neck as he lay asleep in his tent fully armed. The blow was so skilfully given that he died without a groan, and the murderers were able to escape to the Roman camp. From Cæpio, however, they received nothing but the remark that the Romans did not approve and could not reward soldiers who slew their own general. One is glad to record the disappointment of such villains, but it is not easy to understand the unblushing assurance with which Roman historians inveigh against the "_Punic faith_," as they are pleased to call it, of Hannibal. The war was carried on for a time, but the Lusitanians could find no competent successor to Viriathus and were compelled to submit.