In April 680, Yazid I succeeded his father Muawiyah as the new caliph. Yazid immediately instructed the governor of Medina to compel Hussayn and few other prominent figures to pledge their allegiance (Bay'ah). Husayn, however, refrained from it believing that Yazid was openly going against the teachings of Islam in public and changing the sunnah of Muhammad. He, therefore, accompanied by his household, his sons, brothers, and the sons of Hasan left Medina to seek asylum in Mecca.
On the other hand, the people in Kufa who were informed about Muawiyah 's death, sent letters urging Husayn to join them and pledge to support him against Umayyads. Husayn wrote back to them saying that he would send his cousin Muslim ibn Aqeel to report to him on the situation. If he found them united as their letters indicated he would speedily join them, because Imam should act in accordance with the Quran, uphold justice, proclaim the truth, and dedicate himself to the cause of God. The mission of Moslem was initially successful and according to reports 18,000 men pledged their allegiance. But situation changed radically when Yazid appointed Ubayd Allah ibn Ziyad as the new governor of Kufah, ordering him to deal severely with Ibn Aqeel. Before news of the adverse turn of events arrived in Mecca, Husayn set out for Kufa.
On the way, Husayn found that his messenger, Muslim ibn Aqeel, was killed in Kufa. He broke the news to his supporters and informed them that people had deserted him. Then, he encouraged anyone who so wished, to leave freely without guilt. Most of those who had joined him at various stages on the way from Mecca now left him. Later, Husayn encountered with the army of Ubaydullah ibn Ziyad in his path towards Kufa. Husayn addressed the Kufans army, reminding them that they had invited him to come because they were without an Imam. He told them that he intended to proceed to Kufa with their support, but if they were now opposed to his coming, he would return to where he had come from. However, the army urged him to choose another way. Thus, he turned to left and reached Karbala, where the army forced him not to go further and stop at a location that was without water.
Umar ibn Sa'ad, the head of Kufan army, sent a messenger to Husayn to inquire about the purpose of his coming to Iraq. Husayn answered again that he had responded to the invitation of the people of Kufa but was ready to leave if they now disliked his presence. When Umar ibn Sa'ad, the head of Kufan army, reported it back to Ubaydullah ibn Ziyad, the governor instructed him to offer Ḥusayn and his supporters the opportunity to swear allegiance to Yazid. He also ordered Umar ibn Sa'ad to cut off Husayn and his followers from access to the water of the Euphrates.
Name of the Karbala Martyr Husayn with Islamic calligraphy in Hagia Sophia Mosque.
On the next morning, as ʿOmar b. Saʿd arranged the Kufan army in battle order, Al-Hurr ibn Yazid al Tamimi challenged him and went over to Ḥusayn. He vainly addressed the Kufans, rebuking them for their treachery to the grandson of Muhammad and was killed in the battle.
The Battle of Karbala lasted from morning till sunset of October 10, 680 (Muharram 10, 61 AH) all Husayn's small group of companions and family members (in total who were around 72 men and few ladies and children) fought with a large army under the command of Umar ibn Sa'ad. and were killed near the river (Euphrates) where they were not allowed to get any water from. The renowned historian Abū Rayḥān al-Bīrūnī states; "… then fire was set to their camp and the bodies were trampled by the hoofs of the horses; nobody in the history of the human kind has seen such atrocities." Before being killed, Husayn said "If the religion of Muhammad was not going to live on except with me dead, let the swords tear me to pieces."[unreliable source?] Once the Umayyad troops had mass murdered Husayn and his male followers, they looted the tents, stripped the women of their jewelry, and took the skin upon which Zain al-Abidin was prostrate. It is said that Shemr was about to kill him but Husayn’s sister Zaynab was able to make Umar ibn Sa'ad, the Umayyad commander to let him alive. He was taken along with the enslaved women to the caliph in Damascus, and eventually he was allowed to return to Medina.