What is Shia Islam?

Shi'a Islam (Shī‘a Arabic: شيعة; šīʿa is collective; Shī‘i, šīʿi, is singular), is the second largest denomination of Islam, after Sunni Islam. Shi'a Muslims, though a minority in the Muslim world, constitute the absolute majority of the populations in Iran, Azerbaijan, Bahrain and Iraq, as well as a plurality in Lebanon. They also constitute over 45% of the population in Yemen, over 35% of the population in Kuwait, 10-15% of the population of Saudi Arabia, 30% of the population in Turkey, 20% of population of Syria, 25% of the population in Albania, and 20% of the population in Pakistan. It has been estimated that there are approximtaley 10-15 million Shias in India, around 10-15% of the total Muslim population of India. There are an estimated 130 to 190 million Shi'a, 10-15% of the world's Muslim population.[1]

The Shi'a adhere to the Quran and teachings of the final Prophet of Islam, Muhammad, and in contrast to other Muslims, believe that his family, the Ahl al-Bayt (the People of the House), including his descendants known as Imams, have special spiritual and political rule over the community.[2] Unlike Sunni Muslims, the Shi'a believe that Ali ibn Abi Talib, Muhammad's cousin and husband of his daughter, Fatimah, was the true successor to Muhammad who was appointed by God and his prophet, and thus reject the legitimacy of the first three Rashidun caliphs.[3]
The Shi'a faith is vast and inclusive of many different groups. There are various Shi'a theological beliefs, schools of jurisprudence, philosophical beliefs, and spiritual movements. Shi'a Islam embodies a completely independent system of religious interpretation and political authority in the Muslim world. The Shi'a identity emerged soon after the death of Muhammad, and Shi'a theology was formulated in the second century[4] and the first Shi'a governments and societies were established by the end of the third century.
Shi'a Islam is divided into three branches. The largest and best known are the Twelver (اثنا عشرية iṯnāʿašariyya) which forms a majority of the population in Iran, Azerbaijan, Bahrain, Iraq,India and Pakistan. The term Shi'a often refers to Twelver Shi'a only. Other smaller branches include the Ismaili and Zaidi, who dispute the Twelver lineage of Imams and beliefs.[5]

What Is Sunnism or Ahl as-Sunnah wa’l-Jamā‘h ?

Sunni Islam is the largest denomination of Islam . Sunni Islam is also referred to as Sunnism or as Ahl as-Sunnah wa’l-Jamā‘h (Arabic: أهل السنة والجماعة) (people of the example (of Muhammad) and the community), or Ahl as-Sunnah (Arabic: أهل السنة ) for short. The word Sunni comes from the word Sunnah (Arabic : سنة ), which means the words and actions [1] or example of the Islamic prophet Muhammad.

Historically, Sunni Islam has often been defined only in contrast with other denominations or schools of thought, such as Shia Islam, hanafiyah, Mu'tazila and others, considering itself to be the orthodox form of Islam.[citation needed] As such, a case is sometimes made that Sunnism is as old as Islam itself,[citation needed] or at least dates back to the first civil war in Islam from 656 to 661. However, in terms of doctrine and theology, and in the sense of considering itself a separate denomination, Sunni Islam is younger than that, making it somewhat misleading to talk about Sunnites in a 7th century context.
Sunni Islam was under the authority of the Caliph from Muhammad's death in 632 until the abolition of the caliphate by Mustafa Kemal Atatürk in 1924. Since then, no central international authority exists; many countries have a Grand Mufti or other official who holds the highest religious authority in the country. However, during all of Islam's history, independent religious scholars - the ulama - have held great influence in religious matters. During the first centuries of Islam, when the Umayyad and Abbasid caliphs were the worldly rulers of the Muslim world as well as the highest religious authorities of Sunni Islam, this led to some power struggles between the caliphate and the ulama. As the worldly power of the caliphate declined from the 9th and 10th century onwards, and as the religious law became more codified and exhaustive due to the efforts of the ulama, the caliphate's religious influence decreased as well.

Source :Wiki