Titus Livius (Livy), The History of Rome, Book 10
Rev. Canon Roberts, Ed.

10. Meantime the siege of Nequinum was dragging slowly on and time was being wasted. At length two of the townsmen, whose houses abutted on the city wall, made a tunnel, and came by that secret passage to the Roman outposts. [2] They were conducted to the consul, and undertook to admit a detachment of soldiers within the fortifications and the city walls. It did not seem right to reject their proposal, nor yet to accept it offhand. [3] One of them was instructed to conduct two spies through the underground passage; the other was detained as a hostage. [4] The report of the spies was satisfactory, and 300 soldiers, led by the deserter, entered the city by night and seized the nearest gate. This was broken open, and the consul with his army took possession of the place without any fighting. Thus Nequinum passed into the power of Rome. [5] A colony was sent there as an outpost against the Umbrians, and the place was called Narnia from the river Nar. The army marched back to Rome with a large amount of spoil.

This¹ year the Etruscans determined to break the truce, and began to make preparations for war. [6] But the invasion of their country by an enormous army of Gauls —the last thing they were expecting —turned them for a time from their purpose. [7] Trusting to the power of money, which with them was very considerable, they endeavoured to convert the Gauls from enemies into allies in order that they might combine their forces in an attack on Rome. The barbarians did not object to an alliance, the only question was as to the amount of pay. [8] After this had been agreed upon and all the other preparations for war had been completed, the Etruscans called upon the Gauls to follow them. They refused to do so, and asserted that they had not taken the money to make war on Rome. [9] Whatever they had received had been accepted as compensation for not devastating the land of Etruria or subjecting its inhabitants to armed violence. [10] However, they expressed their willingness to serve if the Etruscans really wished them to do so, but only on one condition, namely that they should be admitted to a share of their territory and be able to settle at last in a permanent home. [11] Many councils were held in the various cantons to discuss this proposal, but it was found impossible to accept the terms, not so much because they would not consent to any loss of territory as because they dreaded the prospect of having as their neighbours men belonging to such a savage race. [12] The Gauls were accordingly dismissed, and carried back with them an enormous sum of money gained without labour and without risk.

The rumour of a Gaulish invasion in addition to the Etruscan war created alarm in Rome, and there was less hesitation in concluding a treaty with the Picentes.