de bello gallico, 5.48

Caesar, his plan having been approved, although having been disappointed in his idea of three legions he had returned to two, yet placed his one aid for the common safety in speed. He comes into the territory of the Nervii by long marches. There he learns from captives what things are being born in the camp of Cicero, and in how much danger the situation is. Then with great rewards he induces a certain man from the Gallic cavalry to carry a letter to Cicero. This he sends written in Greek letters, lest, with the letter having been intercepted, our plans should be learned by the enemy. He warns him, if he should be unable to enter, to throw his spear with the letter fastened to the thong, within the fortifications of the camp. He writes in the letter that, having set out with his legions, he will quickly be there: he urges (him) to uphold his former valor. The Gaul, having feared danger, threw his spear as he had been ordered. This, by chance, stuck to a tower and, not having been noticed by our men for two days, was seen by a certain soldier on the third day, having been taken down, it was carried to Cicero. That man, it having been read (by him), read it aloud in an assembly of the soldiers, and the greatest joy moves all. Then the smoke of the fires was seen in the distance, a circumstance which banished all doubt of the arrival of the legions.