Hussein ibn Ali

Al-Hussein ibn Ali ibn Abi Talib (also spelled Hussayn) (Arabic: الحُسین بن علی بن أبی طالب‎) (8 January 626 CE – 10 October 680 CE) (3rd Sha'aban 4 AH – 10th Muharram 61 AH) was the son of Ali ibn Abi Ṭalib (final Rashidun Caliph and first Shia Imam) and Fatimah Zahra (daughter of the Islamic prophet Muhammad) and the younger brother of Hasan ibn Ali. Hussein is an important figure in Islam as he is a member of the Ahl al-Bayt (the household of Muhammad) .

Hussein is highly regarded by Shia as a martyr because he refused to pledge allegiance to Yazid I, the Umayyad caliph. He refused to pledge allegiance to what he considered the unjust rule of the Umayyads. As a consequence fearing bloodshed, he left his home town and heading for Kufa, On the way his caravan was intercepted and he was killed and beheaded in the Battle of Karbala in 680 (61 AH) by Shimr Ibn Thil-Jawshan^[ The annual memorial for him, his family, his children and his As'haab (companions) is called Ashura (tenth day of Muharram) and is a day of mourning for Shia Muslims.

http://en.wikipedia.org/wiki/Hussein_ibn_Ali

حسین بن علی بن ابی‌طالب، امام سوم شیعیان است. سجاد، چهارمین امام شیعیان فرزند وی است. او فرزند علی بن ابی طالب و فاطمه و نوه ی محمد بن عبدالله، پیامبر اسلام است. حسین بن علی در تاریخ ۳ شعبان ۴ هجری قمری در مدینه زاده شد و در ۱۰ محرم ۶۱ در کربلا واقع در عراق کنونی در نبرد کربلا کشته شد. 

http://en.wikipedia.org/wiki/Hussein_ibn_Ali