In 680 Ibn al-Zubayr fled Medina for Mecca. Hearing about Husayn's opposition to Yazid I, the people of Kufa sent to Husayn asking him to take over with their support. Al-Husayn sent his cousin Muslim bin Agail to verify if they would rally behind him. When the news reached Yazid I, he sent Ubayd-Allah bin Ziyad, ruler of Basrah, with the instruction to prevent the people of Kufa rallying behind Al-Husayn. Ubayd-Allah bin Ziyad managed to disperse the crowd that gathered around Muslim bin Agail and captured him. Realizing Ubayd-Allah bin Ziyad had been instructed to prevent Husayn from establishing support in Kufa, Muslim bin Agail requested a message to be sent to Husayn to prevent his immigration to Kufa. The request was denied and Ubayd-Allah bin Ziyad killed Muslim bin Agail. While Ibn al-Zubayr would stay in Mecca until his death, Husayn decided to travel on to Kufa with his family, unaware of the lack of support there. Husayn and his family were intercepted by Yazid I's forces led by Amru bin Saad, Shamar bin Thi Al-Joshan, and Hussain bin Tamim, who fought Al-Husayn and his male family members until they were killed. There were 200 people in Husayn's caravan, many of whom were women, including his sisters, wives, daughters and their children. The women and children from Husayn's camp were taken as prisoners of war and led back to Damascus to be presented to Yazid I. They remained imprisoned until public opinion turned against him as word of Husayn's death and his family's capture spread. They were then granted passage back to Medina. The sole adult male survivor from the caravan was Ali ibn Husayn who was with fever too ill to fight when the caravan was attacked.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What did Ubayd-Allah bin Ziyad rule?
Basrah