The knowledge of smelting and working in iron, like most other arts, came from the East. Iron was especially valued for purposes of war, of which indeed it was regarded as the symbol, being called "Mars" by the Romans.[6] We find frequent mention of it in the Bible. One of the earliest notices of the metal is in connexion with the conquest of Judea by the Philistines. To complete the subjection of the Israelites, their conquerors made captive all the smiths of the land, and carried them away. The Philistines felt that their hold of the country was insecure so long as the inhabitants possessed the means of forging weapons. Hence "there was no smith found throughout all the land of Israel; for the Philistines said, Lest the Hebrews make them swords or spears. But the Israelites went down to the Philistines, to sharpen every man his share, and his coulter, and his axe, and his mattock." [7] At a later period, when Jerusalem was taken by the Babylonians, one of their first acts was to carry the smiths and other craftsmen captives to Babylon.[8] Deprived of their armourers, the Jews were rendered comparatively powerless. It was the knowledge of the art of iron-forging which laid the foundation of the once great empire of the Turks. Gibbon relates that these people were originally the despised slaves of the powerful Khan of the Geougen. They occupied certain districts of the mountain-ridge in the centre of Asia, called Imaus, Caf, and Altai, which yielded iron in large quantities. This metal the Turks were employed by the Khan to forge for his use in war. A bold leader arose among them, who persuaded the ironworkers that the arms which they forged for their masters might in their own hands become the instruments of freedom. Sallying forth from their mountains, they set up their standard, and their weapons soon freed them. For centuries after, the Turkish nation continued to celebrate the event of their liberation by an annual ceremony, in which a piece of iron was heated in the fire, and a smith's hammer was successively handled by the prince and his nobles.