Our Holy Prophet Muhammad al-Mustafa (S.A.W.), his daughter Fatimah al-Zahra’ (S.A.) and. the 12 Imams form the group of 14 Ma’sumeen (Infallible and sinless ones.)
The IMAMS are twelve as follows:
1. Ali al-Murtada, son of Prophet's uncle, Abu Talib, and married to Our Lady of Light, Fatimah, the daughter of the Holy Prophet. 23 B.H. - 40 A.H.
2. Hasan al-Mujtaba (the chosen), elder son of Ali and Fatimah 3 A.H. - 50 A.H.
3. Husain Sayyid-us-Shuhada, (the Chief of the martyrs), second son of Ali and Fatimah. 4 A.H. - 61 A.H.
4. Ali Zain al-‘Abidin 38 - 95 A.H.
5. Muhammad al-Baqir 57 - 114 A.H.
6. Ja’far as-Sadiq (the True) 83 - 148 A.H.
7. Musa al-Kadhim (the Patient) 128 - 183 A.H.
8. Ali ar-Raza (the accepted) 153 - 203 A.H.
9. Muhammad at-Taqi (the Pious) 195 - 220 A.H.
10. Ali an-Naqi (the Pure) 214 - 254 A.H.
11. Hasan al-Askari 232 - 260 A.H.
12. Muhammad al Mahdi: 15 Sha'aban 255, the Imam of our time.
These are the only rightful Imams. There are no more than 12 Imams. The Twelfth Imam is alive till this day, but is hidden, and will reappear at a time appointed by Allah. He is the awaited one and the Mahdi who will revive and spread Islam throughout the world.
NOTE: Whenever we utter or hear the name of our Prophet, we should recite Salawat. We should say, 'Alayhis-salaam' (Peace of Allah be on him) whenever we utter or hear names of Ma’sumeen. Similarly we should stand up, as a mark of reverence, whenever we utter or hear the name of the Imam of our time, (twelfth Imam).