I want to know the answer to the following question:
What did Ubayd-Allah bin Ziyad rule?
All the background I'm provided with is that "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.". Is that enough to answer the question?
Answer: yes