Arguments for the Celtiberian source of the weapon have been reinforced in recent decades by discovery of early Roman "gladii" that seem to highlight that they were copies of Celtiberian models. The weapon developed in Iberia after La Tène I models, which were adapted to traditional Celtiberian techniques during the late 4th and early 3rd centuries BC. These weapons are quite original in their design, so that they cannot be confused with Gallic types. As for the origin of the word "gladius", one theory proposes the borrowing of the word from *"kladi"- during the Gallic wars, relying on the principle that "K" often became "G" in Latin. Ennius attests the word "gladius" may have replaced "ensis", which until then was used mainly by poets.