Answer:
The basis of the division was disagreements over the successor of Muhammad, after the prophet died.
Explanation:
Some people, who would become the Shia, believed that his successor should be a member of the prophet's family, and as a result, they supported Alí, Muhammad's cousin, who has married to Fatima, Muhammad's sisters.
Other people, who would become the Sunni, believed that the successor should be someone chosen by the people on the basis of merit.
The Sunni won out, and chose Abu Bakr as the successor of Muhammad. However, years later, Alí would become Caliph, but shortly after he was assassinated. His son, Hussein, was also assassinated in Iraq, and is considered a martyr in Shia tradition.
During long periods of history, Sunnis and Shiites have coexisted peacefully, but conflcts have arisen in the twentieth century, represented in a geopolitical struggle between Iran, the largest Shia-majority nation, and Saudi Arabia, the political and religious center of Sunni-Islam. (The largest Sunni-majority nation is Indonesia).
Explanation:
