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Smooth stones shot with a sling…are more dangerous than any arrows, since while leaving the limb intact they inflict a wound that is still lethal, and the enemy dies from the blow of the stone without loss of blood…This weapon should be learned by all recruits with frequent exercise, because it is no effort to carry a sling. It often happens too that warfare is carried on in stony places, that some mountain or hill has to be defended…
Vegetius: De Re Militari
Druisius, one of the main characters in my newest book, Empress & Soldier, is a new recruit facing his first battle, defending a mountain pass. In the vanguard of the troops facing the enemy are the slingers. (No, this isn’t historically correct: what I write isn’t. It’s a created world that looks a lot like ours, but I’m not bound by absolute accuracy.)
Slings are an ancient weapon, most likely in use long before any written record. The first written record in the western world is the story of David and Goliath in the Old Testament of the Bible (1st Samuel), thought to have been written about the 6th century BCE. Used across the world, the oldest-known slings are from coastal Peru, radio-carbon dated to c. 2500 BCE.
Roman slingers, which I am using as my model, used lead sling-bullets: the density of lead means that the mass of a sling-bullet made from the metal is much greater than one of stone. Lead sling-bullets could therefore be small, able to travel further than a stone of the same mass due to less resistance in the air, and difficult to see in flight. A painful projectile, with larger ones capable of speeds up to 160 kph. As archaeologist John Reid of the Trimontium Trust told Scientific American, it could take the top of a head off. Romans (and Greeks) literally added insult to injury: bullets were sometimes inscribed with images of snakes or scorpions, or inscriptions such as ‘catch!’.

Perhaps the most interesting of all the sling bullets found from the Roman period are those from Burnswark, or Birrenswark, Hill in southwestern Scotland. In the second century CE, troops under the command of Quintus Lollius Urbicus, the Roman governor of Britannia (himself following orders from Antonius Pius, the Roman Emperor) attacked the hillfort of the Caledonian people here. Archaeological investigations at the site discovered about twenty percent of the sling bullets were smaller than average, and had holes drilled into them. These bullets whistle as they fly. Their assumed purpose is to terrify the enemy: small, stinging, whistling projectiles, almost like a swarm of biting insects.
Druisius isn’t a slinger; he’s infantry, a foot soldier using shield and sword. But he sees the value of the sling in his first battle. Will he ever use it? You may have to read Empress & Soldier to find out!
References:
Translated Texts for Historians Volume 16: Vegetius: Epitome of Military Science. N.P. Milner, Translator. Liverpool University Press, 1996. pp 16-17
Whistling Sling Bullets Were Roman Troops’ Secret Weapon. Tom Metcalfe, LiveScience on June 14, 2016: https://www.scientificamerican.com/article/whistling-sling-bullets-were-roman-troops-secret-weapon/
Burnswark Hill: https://en.wikipedia.org/wiki/Burnswark_Hill#Battle_details