The most ancient writing system, known as the Old Turkic alphabet, disappeared after the Volga Bulgars converted to Islam. Later, the Arabic script was adopted. After the Mongol invasion, writing degraded. After Peter the Great's reforms Chuvash elites disappeared, blacksmiths and some other crafts were prohibited for non-Russian nations, the Chuvash were educated in Russian, while writing in runes recurred with simple folk.