The division between Shia and Sunni Muslims originally arose over?

Answer 1

History of the Shi'ites

The Islamic religion was founded by Muhammed in the seventh century. In 622 he founded the first Islamic state, a theocracy in Medina, a city in western Saudi Arabia located north of Mecca.
There are two major branches of the religion he founded.

The largest group, called the Sunnis believe that the first four caliphs--Muhammed's successors--rightfully took his place as the leaders of Islam. They recognize the heirs of the four caliphs as legitimate religious leaders. These heirs ruled continuously in the Arab world until the break-up of the Ottoman Empire following the end of the First World War.

The smaller of the major groups are the Shi'ites. There are a number of subdivisions under the 'umbrella' of 'Shi'a' and although they differ in the details all of them believe that only the heirs of the fourth caliph, Ali, are the legitimate successors of Muhammed.

The Shi'ites call these successors Imams. Shi'ites do not accept that the Imam is to be only a political leader but they believe that they are literally 'manifestations of God', they are sinless, infallible and the bringers of true understanding to all humanity. They are referred to within the Shi'ite tradition as being masum, that is, free from error or sin.

The last Imam, the Mahdi, is believed not to have died but to be in hiding and Shi'ites believe that he will appear at the end of time in order to bring about the victory of the Shi'a faith (see third paragraph below).

The main groups under the Shi'ite umbrella are the Zaydiyyah or Fivers, the Isma'iliyyah or Seveners and the Imamiyyah or Twelvers. The numbers five, seven and twelve refer to the last authorised interpreter of the law or Imam that each group accepts. Of the three the Twelvers are the biggest & it was in 931 that the Twelfth Imam disappeared.

This was a seminal event in the history of these Shi'ite Muslims. According to R. Scott Appleby, a professor of history at the University of Notre Dame, "Shi'ite Muslims, who are concentrated in Iran, Iraq, and Lebanon, [believe they] had suffered the loss of divinely guided political leadership" at the time of the Imam's disappearance. Not "until the ascendancy of Ayatollah Ruhollah Khomeini in 1978" did they believe that they had once again begun to live under the authority of a legitimate religious figure.

The other important concept in Shi'ite Islam concerning the Imam (regardless of whether he was the Fifth, the Seventh or the Twelfth) is that he will return. He is called the Mahdi and will bring about the Kingdom of God on earth after an apocalyptic battle between the forces of Islam and the rest of the world. [Note that other groups descended from Shi'ia Islam such as the Babis and Baha'is define the 'battle at the end of time' as a symbolic or metaphysical one rather than an actual battle.]

A useful site for information on the various groups is the Overview of World Religions site hosted by St Martin's College in the UK.

http://philtar.ucsm.ac.uk/encyclopedia/islam/shia/index.html

Answer 2

The division between Shia and Sunni Muslims originally arose over