In Karbala event we observe, Yazid’s attempt to secure allegiance from Imam Husayane on the one hand, and Kufa’s invitation of Imam Husayn on the other. But the very important and noticeable point is Imam’s criticizing Yazid and his government without considering the aforementioned points. He criticized corruption, cruelty, and venality in Yazid’s system. He encourages biding to honour and probiding to devil. As a matter of fact all the three reasons mentioned were important for Imam to start his reaction against Yazid, but let’s see which of them has been the most influential one!?
When Ali (A.) was killed by Kharijites, Muawiya became the caliph and remained in control more than ever. Imam Hassan (Ali(A.))’s son tried his best to dethnone Mu’awiya and refresh the Muslim world, but his army was not qualified enough to obey him regularly. Therefore, he concluded a temporary contract with Mu’awiya according to which the caliphate position was given to Hassan (A.) after Muawiya’s death, and in case of the death of Imam Hassan, this position was to be given to Imam Al-Husayn. Mu’awiya poisoned Imam Hassan and tried to establish a hereditary ruling system which was an innovation (bid’a) in religious matters.
Before this bid’a, the caliphate system was based on two types of thought and knowledge.
a.; the person qualified for caliphate position was the one selected by the prophet.
b.; it is people’s right to select a caliph for their own nation.
Mu’awiya was willing to capture caliphate position and maintain it in his family as a hereditary form, but he was hesitating: The person who encouraged Mu’awiya and Yazid to do so was al-Mughira b. Shu’ba: The caliph Umar appointed him governor of Basra. When Mua’wiya disposed him from his position, he went to Yazid and encouraged him to be his father’s successor. The reason lies in the fact that al-Mughira wanted to be governor of Kufa or Basra. Yazid informed al-Mughira that this actin woul not be possible and the ground needs to be paved more profoundly. Al-Mughira believed that Syria (Sham) people would approve whatever issued by Mu’awiya, and he added that Marwan Ib. al Hakam will justify people in Medina and he, himself will preside people in Kufa.
Yazid discussed the ussue with Muawiya, and he called out Mughira. Al-Mughira convinced Mu’awiya and received of governor the position of Kufa and Basra for the 2nd time. This happened after Imam Hassan’s martyrdom. People resisted Marwan and al-Mughira in Medina and Kufa, hence, Mu’awiya himself went to Medina. He was widely in control within the Islamic world then, and expanded Muslim borders up to North African and China, he was seen not just as the man who perverted the caliphate into kingship, but also as a clever and successful ruler, though the legitimacy of his caliphate being a far more important issue than its historical nature, Meanwhile, he made his greatest mistake in relation to foreign policy to hold his incompetent son in power. When the issue was not admitted by the people, he concluded a peace contract with Rome emperor, being the most powerful enemy of Islam, and asked him to support Yazid.
When he was in Medina he visited three influential figures of the city; Al-Husayn b. Ali, Abdullah, b Umar, and al. Zubayr. He tried to convince them to recognize Yazid but they refused.
Mu’awiya was much too anxious about Yazid’s state and advised him some important points, if he followed, undoubtedly, he could have ruled over Muslim territories a bit longer: “Oh, son I’ve paved the way for your kingdom and ruling, Arab rivals are under your control now. Hejaz (al-Hijaz) people are your relatives, respect them the best, and manage them orderly. If they asked you to change a ruler or governor do it as soon as possible, since disposing one is easier than confronting thousands of swords. Damascus people will always help you, ask them for help whenever needed and send them back to their county when  the problem is over. Son, nobody will oppose you but three people. Husayn b. Ali, Abdullah, b. Umar, and al-Zubayr. If al-Husayn rejected you and was invited by Kufa people, and you overcame him, do not kill him because he is your own cousin and he is respected by Muslims, he is the prophet’s grandson. Abdullah will recognize you, if he is left alone, and al-Zubayr will reject you, kill him and tear him limb to limb. Keep your relatives and be kind to them.
Mu’awiya was aware that these people will not recognize Yazid, since all of them were sons of previous caliphs themselves. On the other hand, they were more legitimate thean Yazid to rule over the Muslim territories.
Unfortunately Yazid did not take his father’s advice seriously and faild to maintain and preserve Amir’s (Mu’awiya) throne, and fifty –year efforts. Being a man of leisurly life, he acted so illogically that damaged Banu-Umayya and Abu-Sufyan and corrupted Islamic society then.
After Mu’awiya’s death, Yazid sent a letter to Walid b. Abu Sufyan, governor of Medina to inform him of the issue and asked him to secure allegiance of the 3 people mentioned. Imam Hussayn refused to recognize him and took refuge in Mecca. He did it to show his disagreement, in Mecca he could announce this rejection and disagreement more forcefully, and even if he were killed there he could be more successful and influencial. He then stayed in Mecca during Shaban, Ramadan, Shawal and Zighade. He left there for Iraq, Kufa, in Zihajje, 8th. Muslim world in that time was having three important and significant centers, namely, Medina; center of business, Sham(Damesscus) center of government, and Kufa, former government and ruling center.
Kufa was a recently established city: It was founded by Sa’d b. Abi Waggas in 638. It was the hotbed of political movements and its people sent letters to Imam Husayn and confessed that they would help him against Yazid. Imam al-Husayn knew that those people were not that trustable. In addition, he was in Mecca when he received the letters, better say, he had started his movement and was preaching against Yazid and Kufa’s letters were in the 2nd `degree of importnce to him. Abbas reminded Imam Husayn of the fact that Kufa is not the right place to leave for, but it was not wise to stay in Mecca either, because Yazid missioners could kill Imam and rumor around that he was killed because of a personal confront or action. There was no other way around; he had to leave Mecca for Iraq, though he knew Kufa people will not keep their promise and might turn to be against him. Sham (Damascus) people also were supporting Banu-Umayya and Abu-Sufyan family the same as before. They had revealed it through eighteen month of war against Kufa when Ali(A.) was the caliph, during siffin war.
If Imam Husayn recognized Yazid, he had approved the change from caliphate to hereditary kingdom. On the other hand, Yazid was apparently showing corruption, what other Banu-Umayya caliphs never tried apparently, it is said that Mu’awiya was a man corruption and leisurely life but he was very restrictive and conservative. Yazid, however, did not notice islamic traditions and did not respect Muslim world. He disregarded the fact that millions Muslims from various races in Asia, Africa, and Europe were unique and united since they thought they were ruled by a Muslim leader and caliph; if they became aware of the facts about how Yazid lived, they would announce autonomy and independence. Imam Husayn was against Yazid because Islam was in danger, not because of the willingness towards caliphate position or for material reasons. This is why his movement has been everlasting and unique. Even if Yazid did not ask Imam to recognize him, Imam would rise against him because he was illegitimate and unloyal to rule over Muslim world.