Twelve Imam (Aimmah) of Shia Islam

Belief in Twelve Imam (Aimmah) forms a part of Principles/ Beliefs/ Root/ Tenets of Faith ( Usul Deen). Prophet Mohammed had declared that there will follow a series of twelve vice-regent of his, they would be official spokespersons of Islam. Final authority of Islam on Earth. Their span would continue up to the day of Resurrection, and Islam will remain pure under their guidance. They would be caliphs of God on Earth, only they would interpret the canon of Islam; and the Holy Qur'an. All Twelve Imams are immaculate and infallible, thus their can be no possibility for errors in Islamic interpretation and Islam will remain uncontaminated from errors.

Prophet Mohammed had clearly announced that he is leaving two weighty things (Saqalain) as his legacy; the Holy Qur'an and his blood relatives (Itrat), if people remain bonded with them, people will never go astray. Prophet Mohammed had clearly announced Ali s/o Abu Talib, his cousin and son in law as his first legal heir to lead Islam at event of Ghadeer, just after which Islam was declared a complete religion.

Shia, thus take Ali son of Abu talib as first Imam, and the series goes up to twelfth Imam, which is as follow:

1st Imam Ali Murtada 
Son of Prophet's uncle Abu Talib, Imam Ali is Prophet Mohammed's cousin brother as well as his son in law

2nd Imam Hasan Mujtaba 
Son of First Imam Ali, Eldest Grandson of Prophet Mohammed through his daughter Fatima Zahra

3rd Imam Husain Shaheed 
Son of First Imam Ali, Younger Grandson of Prophet Mohammed through his daughter Fatima Zahra, Younger Brother of Second Imam Hasan Mujataba

4th Imam Ali Sajjad, Zainul Aabideen 
Son of Third Imam Husain Shaheed

5th Imam Mohammed Baaqir 
Son of Fourth Imam Ali Sajjad, Zainul Aabideen

6th Imam Ja'far Saadiq 
Son of Fifth Imam Mohammed Baaqir

7th Imam Musa Kaazim 
Son of Sixth Imam Ja'far Saadiq

8th Imam Ali Reda 
Son of Seventh Imam Musa Kaazim

9th Imam Mohammed Jawwad, Taqi 
Son of Eighth Imam Ali Reda

10th Imam Ali Haadi, Naqi 
Son of Ninth Imam Mohammed Jawwaad, Taqi

11th Imam Hasan Askari 
Son of Tenth Imam Ali Haadi, Naqi

12th Imam Mohammed Mahdi 
The Last Imam, son of Eleventh Imam Hasan Askari, he continues to live in state of metaphysical existence since his Occultation (Ghaybah), will Reappear (Zahoor) by command of God, before Resurrection along with Jesus Christ. He will establish Peace, Justice, Law and True Islamic Order.

Oh Allah! Peace and Salutation be upon Mohammed and House-hold of Mohammed.