Bulgarism is a political movement for the use of the Bolgar ethnonym among Kazan Tatars. It rejects the use of Tatar in favor of the Volga Bulgars, who are considered to be the ancestors of modern-day Volga Tatars. Therefore, Bulgarism is a narrow term for those Volga Bulgarians refusing to be called "Tatars".
Further reading
Viktor Aleksandrovich Shnirelʹman, Who gets the past?: competition for ancestors among non-Russian intellectuals in Russia, Woodrow Wilson Center Press, 1996, ISBN 0801852218, 9780801852213. Limited preview at Google Books (Chapter ).