Titus Livius (Livy), The History of Rome, Book 30
Frank Gardener Moore, Professor Emeritus in Columbia University, Ed.

5. After these preparations, summoning the council, he ordered the spies¹ to set forth what information they had to report, and Masinissa as well, who knew everything about the enemy. Finally he laid before them his plan for the following night. [2] To the tribunes he gave orders that, when the council had been dismissed and the trumpets had sounded, they should at once lead their legions out of the camp. [3] In accordance with the orders he had given the standards were first set in motion just before sunset; at about the first watch the column was deployed. At midnight —for it was a march of seven miles —proceeding at a moderate speed they reached the enemy's camp. [4] There Scipio assigned to Laelius a part² of the forces and Masinissa with his Numidians, and bade them burst into the camp of Syphax and set fire to it. [5] He then led Laelius and Masinissa aside separately and implored each of them to make up by [6??] their diligence and alertness for all the foresight of which night deprived them. [7] He was about to attack Hasdrubal, he said, and the Carthaginian camp; but he would not begin until he should see fire in the king's camp. Nor did that delay him long; for as soon as fire was thrown upon the first huts it caught, and then at once laying hold of everything [p. 383]that was near, and so on in unbroken succession, it³ spread hither and thither through the entire camp. [8] Great was the alarm, to be sure, as was inevitable in a fire so widespread in the night; but they thought the blaze accidental, not due to an enemy and war. [9] Pouring out without arms to extinguish the flames, they encountered armed enemies, particularly Numidians posted in suitable places at the ends of the streets by Masinissa, familiar as he was with the king's camp. [10] Many even in their beds and half-asleep were burned to death; many rushing pell-mell in headlong flight were trodden down in the narrow gateways.