 The dispute intensified greatly after the Battle of Karbala, in which Hussein ibn Ali and his household were killed by the ruling Umayyad Caliph Yazid I, and the outcry for revenge divided the early Islamic community, which is known today as Islamic schism to differ from Christian schism that happened later.The present demographic breakdown between the two denominations is difficult to assess and varies by source, but a good approximation is that 85% of the world's Muslims are Sunni and 15% are Shia Muslims, with most Shias belonging to the Twelver tradition and the rest divided between many other groups.Sunnis are a majority in most Muslim communities