Persia was also one of the most important early Muslim nations and influenced much of both Muslim and Arab culture.

A semi-detailed breakdown of Muslim population by cultural grouping goes something like this: These proportions are likely to change slightly in the near future, as Sub-Saharan Africa still has very high population growth rates, while South Asia and the Arab world are for the most part in the midst of a demographic transition and their birthrates are getting much lower very quickly; expect African Islam to get more press in the near future.

The Abbasid Caliphate claimed descent from Abbas, his youngest uncle, the Hashemites from his great grandfather, and the Umayyad Caliphate from Hashim's brother.

The Fatimid caliphate claimed Fatimah, the Prophet's daughter and Ali's wife, and their branch of Shiism was called Ismailism after Ismail ibn Jafar, a descendent of Ali.

Islam is the second-largest religion in the world, after Christianity.

Although it's becoming increasingly important in Western society, especially current affairs and world politics, the three-fourths of the world's population that don't adhere to it have some very strange ideas about what it's like.

It is considered proper to slaughter an animal when it is facing the Qibla.

Furthermore, like certain Protestant denominations, Islam dislikes alcohol and many Muslim states are 'dry', although this is more a legal point than an actual situation (as anyone who has spent a decent amount of time in Tehran or knows anything about Saudi princes can attest).In Turkey, such clothing is forbidden in government/public areas like universities: one President's wife was criticised for wearing it at his swearing-in.In other countries, it's fully enforced by the police.(For more, see Islamic Dress.) On nuns, Islam dislikes the idea that holiness requires retreating from the world, so monasticism is discouraged as an institution.Many Islamic countries do have an enforced death penalty for those who renounce Islam.The Hashemites are still kings of Jordan, briefly of Iraq and were custodians of Mecca until the 1920s.