Ivan III of Russia
A fragile peace was broken in 1467, when Ibrahim of Kazan came to the throne and Ivan III of Russia supported the claims of his ally or vassal Qasim Khan. Ivan's army sailed down the Volga, with their eyes fixed on Kazan, but autumn rains and rasputitsa ("quagmire season") hindered the progress of Russian forces. When frosty winter came, the Russian generals launched an invasion of the northern Vyatka Region. The campaign fell apart for lack of unity of purpose and military capability.