Appian(us) (c.AD 95 – c. 165) was born in Alexandria but went to Rome in c.120 to practice law. We are not entirely sure about what sources he used for his histories.
The following is an adaptation of Appian. The Foreign Wars, trans. Horace White. New York: MacMillan Company, 1899.
§ 1. [c.389 BCE] Afterwards the Boii, the most savage of the Gauls, attacked the Romans. Gaius Sulpicius, the dictator, marched against them, and is said to have used the following stratagem. He commanded those who were in the front line to launch their javelins, and immediately crouch low; then the second, third, and fourth lines to launch theirs, each crouching in turn so that they should not be struck by the spears thrown from the rear; then when the last line had hurled their javelins, all were to rush forward suddenly with a shout and join battle at close quarters. The hurling of so many missiles, followed by an immediate charge, would throw the enemy into confusion. The spears of the Gauls were not like javelins, but what the Romans called pila, four-sided, part wood and part iron, and not hard except at the pointed end. In this way the army of the Boii was completely destroyed by the Romans.
§ 2. [121 BCE] When the Romans asked for their surrender and it was refused, they made war on the Allobroges, under the leadership of Cnæus Domitius. When he was passing through the territory of the Salyi, an ambassador of Bituitus, king of the Allobroges, met him, arrayed magnificently and followed by attendants likewise arrayed, and also by dogs; for the barbarians of this region use dogs also as body-guards. A musician was in the train who sang in barbarous fashion the praises of King Bituitus, and then of the Allobroges, and then of the ambassador himself, celebrating his birth, his bravery, and his wealth; for which reason chiefly their illustrious ambassadors usually take such persons along with them.