were destroyed
... that most Russian cities were destroyed as a result of the Mongol invasion?
... that most Russian cities <b id="mwA7Q"><a href="./Demographic_history_of_Russia" id="mwA7U" rel="mw:WikiLink" title="Demographic history of Russia">were destroyed</a></b> as a result of <a href="./Mongol_invasion_of_Kievan_Rus'" id="mwA7Y" rel="mw:WikiLink" title="Mongol invasion of Kievan Rus'">the Mongol invasion</a>?