Muslims believe that there were many other prophets before Muhammad since dawn of humanity, beginning with the Prophet Adam and including the Prophet Noah (Nuh), the Prophet Abraham (Ibrahim), the Prophet Moses (Musa), and the Prophet Jesus (Isa). They believe that all these prophets were given messages by God of the oneness of God to their communities at different times in history of mankind, but Satan (referred to as 'Shaytan' in Arabic) made the past communities deviate from the message of oneness and other social codes. Muslims believe that the content of the Quran (written in Arabic) is protected by Allah as mentioned in the Quran and is the final message of God for all of mankind until the day of judgment.
Most Muslims belong to one of two groups. The most common is Sunni Islam (75–90% of all Muslims are Sunni Muslims). The second is Shia Islam (10–20% of all Muslims are Shias – also called Shiites). But there are many more groups like the Alevis in Turkey.
With about 1.75 billion followers (24% of the world's population), Islam is the second-largest religion in the world. Islam is also the fastest-growing religion in the world. Islam is also the second-largest and fastest-growing religion in Europe.