Iran is a Shia Muslim majority state often in tension with Sunni states and extremist groups like the Islamic State or al-Qaeda. These attacks are the latest chapter in the story of the centuries-long strained relationship between Sunnis and Shias.
As a scholar of Islam and a public educator, I often field questions about Sunnis, Shias and the sects of Islam. What exactly is the Shia-Sunni divide? And what is its history?
History of divide
Both Sunnis and Shias – drawing their faith and practice from the Quran and the life of the Prophet Muhammad – agree on most of the fundamentals of Islam. The differences are related more to historical events, ideological heritage and issues of leadership.