In 5th century B.C., falcata swords were forged in Toledo by Iberian blacksmiths. They are made with an iron blade inside the exterior design that is made to increase the bluntness of the slash. They were chosen by Hannibal's army and the Roman legions adopted them after witnessing their quality the hard way. The superior swords' fame reached far and wide. Even Japanese Samurai would come to Toledo to have their Katana and Wakizashi forged.
The secret is in its fabrication. The simultaneous forging of hard steel with high contents of carbon and soft steel at very high temperatures (almost 1500 degrees F) obtains the deadly mechanical properties as well as a better fastness to wear.