Tragedy and Battle of Karbala. May peace be upon Yazid! Detailed introduction and Three Dreadful Crimes of Yazid ibn Muawiya.

Battle of Karbala
Please read Hashim, Abdul Muttalib, Abu Talib, Root cause of Division, Uthman, Battle of Jamal and Siffin before this article.
Background
Muawiya’s Rule: Peace Treaty with Hassan and Appointment of Yazid

Ali’s elder son Hassan appointed as Imam and Caliph. But Muawiya in Syria continued his efforts to become the ruler of all the Muslims so the internal fights continued. Hassan was soft in heart and did not like the further shedding of Muslims blood. He made a peace treaty with Muawiya with some conditions and stepped down and Muawiya became the Caliph the ruler of all Muslims. This act was disliked by the Banu Hashim and the Rivalry turned into Umayyah vs. Ahle Bait (family of the Prophet) and a large group of supporters of the family of prophet emerged called Shia. Later Hassan is poisoned and killed in 670 AD dominant opinion is that he was poisoned by his wife on instigation from her close relatives from Banu Ummayah. After this Hussein bin Ali becomes Imam of Ali’s followers.
Yazid’s succession to Muawiyah
In the peace treaty made by Hassan, it was mentioned that Muawiya would not appoint a successor for himself, but Muawiya appointed Yazid and on his death in 680 AD Yazid became Caliph. He was the first person who got caliphate by the appointment of his father in a hereditary manner as opposed to the tradition of previous caliphs.
Husayn Refusal of giving Allegiance to Yazid
Then Hussein, who is another son of Ali from Fatima daughter of Muhammad does not give his allegiance to Yazid. Yazid instructed his Governor Walid in Medina to force him to pledge allegiance to Yazid. In the meantime, a group in Kufa said Hussein that they would support him. Thus Hussain departed for Kufa from Madina. Yazid sends an army to stop them and to eliminate Hussein and his family so that there are no other legitimate claimants to the caliphate.

The Massacre of Karbala
Remeber Hussein is not commanding an army it was just his family and close relatives not more than 100 in number. Yazid’s forces under the command of Umar bin Sad intercept Hussein’s caravan in Karbala, and this is known in the Shia tradition as the Tragedy of Karbala in 680 AD. In which almost all of Hussein’s and prophet Muhammad family members Ahl e Bait massacred even his six month old son is beheaded and killed along with Hussein. After the battle, the army trampled the bodies of the martyrs, attacked the tents of surviving ones, took anything which were left as booty and set fire to the tents. Only one male from Hussein progeny saved which is Due to his illness, his name is Ali known as Zayn al-Abidin and Imam al-Sajjad. He and his sister Zaynab together with other women and children were taken captives by the army of Kufa. They put the heads on swords and spears and took them with the captives to Kufa to Ubayd Allah bin Ziyad and from there to Syria to Yazid.
Aftermath of Karbala
Ali bin Hussain retired after Karbala and Muhammad bin Ali al-Hanafiyyah became the visible head of the house of Ali. It was in his name that Al-Mukhtar Thaqfi rebelled in Kufa in 686 and took revenge of Hussain and Ali Asghar’s martyrdom by killing those persons Harmala bin Kahil, who killed Ali Asghar Sanan bin Anas, who took part in Husayn’s killing, Umar bin Saad, who led the Umayyah army during the Karbala massacre and Shimr bin Thil Jawshan who beheaded Hussein.

Detailed introduction of Yazid: Was Yazid a Muslim?
Karbala is such a big tragedy in human history after Jesus crucifixion that I can go on and be talking about it for days and weeks. Whenever I think about Ali and then about Hussein, I feel the pain they went through all their lives. I wish I could be there in that space time and could fight form there side with their enemies.
May Peace be upon Yazid
Many Muslims defend Yazid: O Muslims you are the worst Nation Sky has ever seen!
But despite all this, there are still some people in Muslims, even some prominent scholars who look like the followers of Yazid and want to defend him by giving him the benefit of the doubt and saying such things as رضي الله عنه radiyAllahu anhu for him. An Arabic phrase meaning, “May Allah be pleased with him. And this is actually not surprising if there are people who are defending Yazid as if from only one male survivor of Hussein we have so many lovers of Hussein and Ali then Yazid and his supporters would have their progeny and followers alive in this world.
Muslims Defend Yazid for following three Reasons:
Hadith of Constantinople
They based their plea on certain excuses like Hadith of Constantinople. A saying of Muhammad in various books including Bukhari international numbering 2924 where those who would participate in the battle of Constantinople were given glad tidings of Paradise by Prophet. They say that because Yazid participated in that battle, he would be among the saved ones. While the fact of the matter is that the army of Yazid was not the first army arrived at Constantinople instead it was the 7th or 8th while in prophet saying it is clearly mentioned that these tidings are for those in the first battle.
Benefit of doubt
Secondly, they defend Yazid and say radiyAllahu anhu for him on the basis that all this is history and we cannot say with surety if Yazid has done all this or not so better give him the benefit of the doubt. I ask you a question if that is the approach then there is no certainty if there were any individuals like Abu Bakr Umar