On Local upper-class' Struggle of Tibet and its Influence from the 13th Century to the Early 19th Century

Since Tibet area was incorporated into the territory of Yuan dynasty in the middle 13th century,the central governments of all historical periods exercised military and administrative jurisdiction over Tibet and made certain achievements in strengthening local administration of Tibet.But there were many drastic contradictions and conflicts in local upper-class' interior of Tibet all the time,these drastic contradictions and conflicts exerted a profound influence on the society of Tibet.