Imam Mahdi(a.s) was born in 15 shaban 255H=869 AD .His kunniat is Abu’l Qasim and his name is Muhammad ibn Hasan ibn ‘Alī. His mother, Her Greatness  Narjir(a.s) (Melika), was a Byzantine princess who pretended to be a slave so that she might travel from her kingdom to Arabia.His father,Imam Hassan al askari(a.s) the eleventh imam .his birth was kept a secret due to the persecution that the  shia were facing during this time at the hands of  Almuatamad  abbasi.After mrtyrd of Imam hassan askari (a.s)his son imam Mahdi(a.s)to be the Imam, appointed by God, to lead the believers of the era. To support Imam Mahdi’s claim,  quote the following Hadith: “I and `Ali are the fathers of this nation; whoever knows us very well also knows Allah, and whoever denies us also denies Allah, the Unique, the Mighty. And from `Ali’s descendants are my grandsons al -Hasan and al- Husayn, who are the masters of the youths of Paradise, and from al- Husayn’s descendants shall be nine: whoever obeys them obeys me, and whoever disobeys them also disobeys me; the ninth among them is their Qa’im and Mahdi. This quote is supported by most Sunnis.