Islam 
Islam is a word which comes from an Arabic root word meaning "submission."  The religion teaches that one can only find peace in one's life by submitting to Almighty God (Allah) in heart, soul and deed. The same Arabic root word gives us "Salaam alaykum," ("Peace be with you"), the universal Muslim greeting.

So, the religion is called "Islam and a person who believes in and consciously follows Islam is called a Muslim, also from the same root word.

In Islam, faith and good works go hand-in-hand. A mere verbal declaration of faith is not enough, for belief in Allah makes obedience to him a duty.  The Muslim concept of worship is very broad. Muslims consider everything they do in life to be an act of worship, if it is done according to Allah's guidance. There are also five formal acts of worship which help strengthen a Muslim's faith and obedience. They are often called the "Five Pillars called the "Five Pillars of Islam."

  
♦ Testimony of faith (Kalima)
   ♦ Prayer (Salat)
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Almsgiving (Zadak)
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Fasting (Sawm)
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Pilgrimage (Hajj)
   
Islam dates back to seventh century Arabia. The Prophet Muhammad, an aristocratic Arabian born and raised an orphan in the city of Mecca, a city sacred to all religions, experienced a revelation in his fortieth year in which the Quran was revealed from God through the archangel Gabriel. Then the Prophet orally transmitted the Quran to others, as he could not read or write.. He began to preach to his own people, most of whom initially persecuted him. After thirteen years of suffering with patience and endurance, he escaped to the nearby city of Medina. A few years later, with an army he had raised, the Prophet raided Mecca and destroyed all elements of any other religion. For over twenty-three years, beginning in 610 AD. , Muslims believe. In it, a cosmology, a theology, and an elaborate eschatology are described. By the end of the Prophet's life in 632 AD., due to the efforts of his raiding armies, almost the entire Arabian Peninsula had converted from paganism to Islam, and within a hundred years, its followers stretched from France to China.
At the death of the Prophet Mohammed, Islam split into two groups, his son-in-law Ali claimed leadership, while his chieftain claimed also claimed leadership. At this time  The Shia followed Ali who was an heir of Mohammed, while the Sunnis followed the rule of Arab tribal leaders, called Caliphs.

Bloodshed frequently erupted between them. According to Shiite belief, the Caliphs were trying to wipe out Ali's line of succession by killing off his heirs, the imams, one by one over the first few centuries of the faith.

Pious Shiites believe that the 10th and 11th of Ali's heirs, Ali Hadi and Hassan Askari, are buried in the shrine in Samarra. Shiites teach that both were poisoned by agents of the Caliph in the 9th century in an attempt to wipe out Ali's line once and for all.

But Shiites believe Askari had a young child, Mohammed al-Mahdi, who disappeared into a cellar near the site of the shrine before he could be killed. Shiites believe Mahdi, the 12th or "hidden imam," will reappear, and that his return will herald a new age, avenging the wrongs done to his ancestors and to the Shiite faithful who have suffered under the rule of Sunni governments for centuries.

"Mahdi is expected to return one day as a messiah," Nakash said. The shrine complex is considered a tangible link to Mahdi.