The Celtic Long Sword was around three feet in length, with a straight, double-edged iron blade. Greek historian Diodorus Siculus descriped the Celtic swords as being "as long as the javelins of other peoples." The hilt had a very small guard, a single-handed grip, and (most noticeably) two backward-curving quillons near the pommel.
The Celtic long sword was primarily a slashing weapon, as the rounded tip was ill-suited for thrusting and stabbing, making it similer to the Khanda. The Celts were famous for their iron working abilities, and some historians even think that the Celts iron should in fact be classfied as steel. According to the show, Celts used the long sword from back of chariots as well. This was successfully tested as the long sword cut a gel head through the nose and to the brain from the back of a chariot.
The Celts prefered way of killing with the long sword was decapitation. After a battle the Celts would hang the heads of their decapitated enemes on their houses, their chariots and their horses. They would also stick the heads on a pole sticking out of the ground outside their house. The Celts kept the heads of their fallen enemes as a trophy and to possess a persons head is to posses a magic power.
When a Celt died he was buried with his sword. His sword was intentionally broken before burial so that only spirits like the deceased Celt could wield it.
Spanish Celtic Long Swords would evolve into the Roman Gladius. Germanic Celts would influence Vikings; leading to their own variation of the Long Sword. The Celtic Long Sword may have eventually evolved into the Scottish Claymore.