Sham-i-Ghareban is a mouring night of Shia Muslims which is observed between 10th Muharram and 11th Muharram. The word Sham means night and Ghareban means poor or oppressed, thus this night remarks sacrifice and tolerance of the oppressed people of Ahlebait a.s. in Karbala. So, it is called Sham-i-Ghareban. On 11th Muharram Ahlebait a.s. reached Kufa in the palace of Ibn Ziyad l.a. It is the main night in Muharram. On this night the Holy Quran is recited, people gather to say Nowha and Marsiya.
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Sham-i-Ghareban Wikipedia(Text) CC BY-SA