Battle of Karbala
The Battle of Karbala was a military engagement that took place on 10 Muharram, 61 AH (October 9 or 10, 680 CE) (Persian: هجدهم یا نوزدهم مهر ماه 51 شمسی‎) [1] [2] in Karbala, in present day Iraq, between Muhammad's grandson Husayn ibn Ali and a military detachment from the forces of Yazid I, the Umayyad caliph. Although the party of Husayn ibn Ali was small and the war didn't take much time, many notable members of the Muhammad's family were involved in it.
This battle is central to Shi'a Muslim belief. The death of Husayn is mourned by an annual commemoration, Ashurah.

Battle based on Islamic traditions

Background
After the passing on of Prophet Muhammad, there was some dissension in the Muslim community as to who should succeed him. The majority of the Muslims accepted the rule of the caliph Abu Bakr and then of the caliphs Umar ibn al-Khatthab, Uthman ibn Affan, and Ali bin Abi Talib. However, Shi'a've believed that Ali ibn Abi Talib, Prophet Muhammad's cousin and son-in-law, who had lived with Prophet Muhammad since he was a child, was the better choice.

Umayyad dynasty Appears
When Uthman was killed by rebels, most of the Ummah (Muslim's nation)pressed Ali ibn Abi Talib to take the caliphate. Their choice was not accepted by all Muslims. Mu'awiya .The Muslim community fell into the First Islamic civil war. Ali was assassinated and power was eventually grasped by Muawiya I after Hasan ibn Ali forced to sign a conditional peace treaty with him stating that shura appoints the caliphate after death of Muawiya I.

Yazid's bid for power: Caliphate changes to Monarchy
Muawiya tried to ensure that his son, Yazid, would be accepted as the next caliph. He required all his supporters to swear allegiance to Yazid before his death. However, when Muawiya died, major famous men such as Abdollah ibn Omar, son of the 2nd caliphate, Husayn ibn Ali and others rejected Yazid as the next caliph. For the opposition parties, this was the right time to any struggle toward power.

Yazid's bid for power: Caliphate changes to Monarchy
Muawiya tried to ensure that his son, Yazid, would be accepted as the next caliph. He required all his supporters to swear allegiance to Yazid before his death. However, when Muawiya died, major famous men such as Abdollah ibn Omar, son of the 2nd caliphate, Husayn ibn Ali and others rejected Yazid as the next caliph. For the opposition parties, this was the right time to any struggle toward power.

Kufa's opposition to Damascus
Husayn, Ali's surviving son by Muhammad's daughter Fatima, was willing to prevent deviation of muslims society from Quran and traditions of prophete Mohammad toward monarchy and tyranny.

Kufa, a garrison town in what is now Iraq, had been his father Ali's capital, and there were still many people in Kufa claiming they are supporters of Ali. Husayn received around 12000 letters from the Muslims of Kufa, saying that they would support him if he claimed the caliphate trying to recover Iraq's power in Islamic countries against Damascus, the capital of Muawiya I father of Yazid.

Accordingly, Husayn left Hajj ceremony toward Kufa with approximately one thousand supporters and family members changing his Hajj to Umrah. He willed before his journey his half-brother Mohammad ibn Hanafiyyah, an old and blind man. Mohammad ibn Hanafiyyah was preventing him from going to Kufah knowing hypocricy and insincerity of its people even with Ali.

Husayn's representative to Kufa, Muslim ibn Aghil, executed before Husayn's departure toward Kufa in 9th of Dhu al-Hijjah by the new governor of the Kufa without any considerable resistance from the people of the Kufa. Almost all the supporters of Husayn from Kufa turned his enemies. But Husayn continued his way toward Kufa even after he received its sad news.

Husayn was intercepted by vanguards of Yazid's army of around 2000 men headed by Hurr ibn Yazid Al-Riyahi. Hurr refused Husayn's request of his return to Medina and also prevented him from advancing toward Kufa or any other directions.

The Battle of Karbala ensued, in which Husayn and all his 72 men were killed, except his 2nd son Ali ibn Husayn who was gravely ill as well as his remaining family composed of children and ladies taken prisoner.

Particulars of the event
According to Shi'a historians, Prophet Muhammad had charged Ali ibn Abi Talib, and after him Ali's sons Hasan and Husayn, with the duty to lead the Muslim community. However, power was usurped by others. Muawiya I's death was seen by Ali's descendants and their supporters as an opportunity to re-establish the proper authority.

They additionally claimed that Hasan had ceded power to Muawiya only after receiving his promise that a shura, a public consultation to choose a new ruler, would be held when Muawiya died. Muawiya had broken that promise when he put his son on the throne; Muawiya, therefore, was to be opposed by all honest Muslims.

Yazid I, the new ruler, feared that Husayn would assert his claims. Therefore he sent an emissary to Husayn demanding his submission, his bay'ah. Husayn believed that he had a duty to refuse submission, and left from Medina to Mecca to perform the Hajj ritual.

When letters came from Kufa assuring him of Kufan support, Husayn set out to raise his banner and stake his claim. Part of the way towards Kufa, word came that Yazid had sent a new governor, Ubayd-Allah ibn Ziyad, with an army, and that the Kufans had submitted rather than fight.

Husayn continued to advance toward Kufa after receiving news of the loss of Kufan support. The Shi'a belief is that he did so in the spirit of self-sacrifice, knowing that he would die and that his death would demonstrate the evil of Yazid's worldly rule.

He and his family and his supporters -- a mere seventy two men -- finally pitched camp at Karbala, close to the city of Kufa in what is now Iraq.

Hussain is surrounded
Yazid's governor, ibn Ziyad, is said by the Shi'a to have sent an army of 30,000 men against Husayn. They surrounded his camp and then opened negotiations with Husayn.

The leader of the force, Umar ibn Sa'ad, finally agreed to Husayn's proposal that the siege be lifted so that Husayn, his family, and his companions could leave Iraq. He sent word to his superiors, asking them to ratify the offer. The governor, ibn Ziyad, liked the proposal, but another Umayyad grandee, Shimr ibn Dhil-Jawshan, vetoed it. Umar ibn Sa'ad was commanded to destroy Husayn or be killed himself.

On the 7th of the month of Muharram, ibn Sa'ad moved his troops closer to Husayn's camp, cutting the camp off from the Euphrates River. The camp now had no supply of water and might be forced to surrender from thirst.

Choice between life and death
On the 9th of Muharram, the camp had exhausted its water and could choose only between surrender and death. Husayn asked ibn Sa'ad for yet more delay, until the next morning, so that he and his men could spend the night praying. Again, ibn Sa'ad granted this request.

Husayn then told his men that he did not intend to surrender, but to fight. Since they were so heavily outnumbered, all of them were sure to die. He told them that if they wished to flee the camp in the middle of the night, rather than face certain death, they were free to do so. None of Husayn's men wished to defect. Instead they displayed their wish of being killed on the name of Husayn repeatedly if they were brought back to life by Allah(T.A)

Day of battle
The next day, Husayn's followers went to the front lines and one by one, addressed their relatives and friends in the enemy forces. They asked them to refuse to fight. Husayn himself addressed the enemy troops. The Shi'a say that his speech was so affecting that one of Yazid's generals, named Hurr who actually stopped Husayn from his journey to Najaf, abandoned Yazid's army and joined Husayn's small force and was the first amongst the Martyrs of Karbala.

Ibn Sa'ad feared that this might be the first of many defections, therefore hurried to join battle. He shot an arrow towards Husayn and the unequal battle began.

First Husayn's friends and followers went out to battle. One by one, loyal men like Hurr, Habib ibn Mazahir, Muslim ibn Ausaja, and Zohair-e-Qain, many of whom were once close companions of Ali ibn Abu Talib, laid down their lives. Then came the relatives' turn. The men of Banu Hashim, the clan of Muhammed and Ali, went out one by one. Casualties included Abbas, the half-brother and flag-bearer of Husayn, Ali Akbar, son of Husayn, Qasim, son of Hasan ibn Ali and nephew of Husayn, and Aun and Muhammad, the sons of Zainab bint Ali.

The women and children were huddled in the tents, waiting for the battle to end. Husayn's son Imam Ali ibn Husayn was there among the women, because he was too ill to fight. Another son, Ali Asghar, was but six months old, and close to death from lack of water.

Husayn took the child in his arms and marched out to face Yazid's army. He asked for water for the child. But Hurmala ibn Kahil, on orders of Umar ibn Sa'ad, shot an arrow at the child. It pierced him in the neck and he died in the arms of his father.

Husayn buried his son and again went out to face the army. He is said to have demonstrated extreme courage and bravery, forcing the enemy into retreat. Eventually, however, as the time for the Asr prayer approached, Husayn desisted. As he dismounted from his steed to offer the prayer, he was attacked by arrows and spears, even though Yazid's army was still too shaken to approach him. However, he began his prayer. As he prostrated on the ground, Shimr ibn Dhil-Jawshan, one of Umar ibn Sa'ad's commanders, approached Husayn and cut off his head. Husayn's head was raised on a spear for all to see. The men took off all valuables from his person, leaving the corpse semi-naked.

Aftermath
Husayn's head was raised on a pike for all to see. His body was looted and then trampled by horsemen.

As night approached, Yazid's army advanced to Husayn's tents. They were looted and set on fire. Jewelry and veils (hijab) were taken from the women, and the children were beaten.

The next day, the women and children were loaded on camels and taken to Yazid's court in Damascus via Kufa. The Shi'a say that the captives were humiliated and harried, so that fatigue, hunger, and thirst were added to their grief at the death of Husayn and his men. Yazid believed that by doing so, he could humiliate and ridicule them to the point where Husayn's followers would lose all public support.

However, during the journey from Kerbala to Kufa, and from Kufa to Damascus, Husayn's sister Zaynab bint Ali and son Ali ibn Husayn gave various speeches that vilified Yazid and told the Muslim world of the various atrocities committed in Kerbala. After being brought to Yazid's court, Zaynab courageously gave a famous speech in which she denounced Yazid's claim to the caliphate and eulogized Husayn's uprising.

The prisoners were held in Damascus for a year, during which Husayn's 4 year old daughter, Sakina bint Husayn, is believed to have passed away due to grief and sorrow. The people of Damascus began to frequent the prison, and Zaynab and Ali ibn Husayn used that as an opportunity to further propagate the message of Husayn and explain to the people the reason for Husayn's uprising. As public opinion against Yazid began to foment in Syria and parts of Iraq, Yazid ordered their release and return to Medina, where they continued to tell the world of Husayn's cause and Yazid's atrocities. The Shiites' commemoration of Ashurah thus began and has persisted to this day.