Husayn ibn Ali (; 11 January 626 – 10 October 680 CE) was an Alid political and religious leader. The second son of Ali and Fatima and a grandson of the Islamic prophet Muhammad, as well as a younger brother of Hasan ibn Ali, Husayn is regarded as the third Imam in Shia Islam after his brother, Hasan, and before his son, Ali al-Sajjad. Husayn is a prominent member of the Ahl al-Bayt and is also considered to be a member of the Ahl al-Kisa and a participant in the event of the mubahala. Muhammad described him and his brother, Hasan, as the leaders of the youth of paradise.
During the caliphate of Ali, Husayn accompanied him in the military campaigns of the First Fitna. After the assassination of Ali, he obeyed his brother in recognizing the Hasan–Mu'awiya treaty, despite being suggested to do otherwise. In the nine-year period between Hasan's abdication in AH 41 (660) and his death in AH 49 or 50 (669 or 670), Hasan and Husayn retreated to Medina, trying to keep aloof from political involvement for or against Mu'awiya I. After the death of Hasan, when Kufans turned to Husayn, concerning an uprising, Husayn instructed them to wait as long as Mu'awiya was alive due to Hasan's peace treaty with him. There, the people of Kufa sent letters to him, invited him to Kufa and asked him to be their Imam and pledged their allegiance to him. On Husayn's way to Kufa with a retinue of about 72 men, his caravan was intercepted by a 1,000-strong army of the caliph at some distance from Kufa. He was forced to head north and encamp in the plain of Karbala on 2 October, where a larger Umayyad army of some 4,000 or 30,000 arrived soon afterwards. Negotiations failed after the Umayyad governor Ubayd Allah ibn Ziyad refused Husayn safe passage without submitting to his authority, a condition declined by Husayn. Battle ensued on 10 October during which Husayn was killed along with most of his relatives and companions, while his surviving family members were taken prisoner. The battle was followed by the Second Fitna, during which the Kufans organized two separate campaigns to avenge the killing of Husayn; the first one by the Tawwabin and the other one by Mukhtar al-Thaqafi and his supporters.
The Battle of Karbala galvanized the development of the pro-Alid party (Shi'at Ali) into a unique religious sect with its own rituals and collective memory. It has a central place in the Shi'a history, tradition, and theology, and has frequently been recounted in Shi'a literature. For the Shi'a, Husayn's suffering and martyrdom became a symbol of sacrifice in the struggle for right against wrong, and for justice and truth against injustice and falsehood. It also provides the members of the Shi'a faith with a catalog of heroic norms. The battle is commemorated during an annual ten-day period during the Islamic month of Muharram by many Muslims especially Shi'a, culminating on tenth day of the month, known as the day of Ashura. On this day, Shi'a Muslims mourn, hold public processions, organise religious gathering, beat their chests and in some cases self-flagellate. Sunni Muslims likewise regard the incident as a historical tragedy; Husayn and his companions are widely regarded as martyrs by both Sunni and Shi'a Muslims.
Early life
Most narrations report that Husayn was born on the 3rd of Sha'ban 4 AH (11 January 626) in Medina and was still a child when his grandfather, Muhammad, died. He was the younger son of Ali, the cousin of Muhammad, and Fatima, the daughter of Muhammad, both from the Banu Hashim clan of the Quraysh tribe. Both Hasan and Husayn were named by Muhammad, although Ali had other names such as "Harb" in mind. Muhammad sacrificed a ram to celebrate Husayn's birth, and Fatima shaved his head and donated the same weight of his hair in silver as alms.
Islamic traditions holds Husayn is mentioned in the Torah as "Shubayr" and in the Gospels as "Tab".
Husayn was raised in Muhammad's household during his early years. The family formed from the marriage of Ali and Fatima was praised many times by Muhammad. In events such as Mubahala and the hadith of the Ahl al-Kisa, Muhammad referred to this family as the Ahl al-bayt. In the Qur'an, in many cases, such as the verse of purification, the ahl al-bayt has been praised.
Madelung notes that numerous narrations showing Muhammad's love for Hasan and Husayn, such as carrying them on his shoulders or putting them on his chest and kissing them on their bellies. Madelung believes that some of these reports may imply a slight preference of Muhammad for Hasan over Husayn, or pointing out that Hasan was more similar to his grandfather.
A hadith in the canonical Sunni collection Sunan al-Tirmidhi states al-Hasan and al-Husayn as the sayyids (“chiefs”) of the youth in Paradise. Madelung adds that this hadith is widely reported.
Other similar Hadiths include: "Whoever loves them loves me and whoever hates them hates me", and "al-Hasan and al-Husayn are the sayyids [masters] of the youth of Paradise". The recent one is used by Shia to prove the right of Imamate for the descendants of Muhammad. is an epithet used by Shias to refer to each of Muhammad's grandsons. Muhammad reported the Karbala incident on several occasions; For example, he gave a small bottle of soil to Umm Salama and told her that the soil inside the bottle would turn into blood after Husayn was killed.
Event of Mubahala
thumb|left|The calligraphy of the names of [[ahl al-kisa and two hadiths of Muhammad on the cloth, probably belonging to Iran or Central Asia]]
In the year 10 AH (631–632) a Christian envoy from Najran (now in northern Yemen) came to Muhammad to argue which of the two parties erred in its doctrine concerning Jesus. After likening Jesus' miraculous birth to Adam's creation — who was born to neither a mother nor a father— and when the Christians did not accept the Islamic doctrine about Jesus, Muhammad reportedly received a revelation instructing him to call them to Mubahala, where each party should ask God to destroy the false party and their families: