How did Imam Hossein (AS) Begin his Imamat?

When Imam Hasan was poisoned, in his will to Imam Hossein he requested to be buried near his grandfather, the Prophet. Imam Hasan did not want any bloodshed during his burial, and in case of any opposition, he requested to be buried near his grandmother, Fatimah bint Asad, in the Baqi’ cemetery.
On the first day as an Imam, Imam Hossein faced a challenge during the burial of his brother. Marwan ibn al-Hakam and his troops, with support from Aisha, one of the Prophet’s wives, did not allow Imam Hasan’s body to get close to the Prophet’s tomb. In the conflict between the people and the troops, many arrows were fired towards Imam Hasan’s body. Imam Hossein controlled the situation and directed the crowd towards the Baqi’ cemetery by reminding them of Imam Hasan’s will.
The conflict during Imam Hasan’s burial was a strong message to Imam Hossein from the Umayyads, that in case of any opposition, he would be faced with their swords. During Muawiyah’s time, Imam Hossein’s life and activities were under intense pressure and surveillance by the government to the extent that even his supporters were sometimes prevented from meeting him freely. Due to this pressure, the number of narrations quoted from Imam Hasan and Imam Hossein during Muawiyah’s time are fewer than those from the other Shia Imams.