Detailed Instructions: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Q: Passage: In 821/822 CE Tibet and China signed a peace treaty. A bilingual account of this treaty, including details of the borders between the two countries, is inscribed on a stone pillar which stands outside the Jokhang temple in Lhasa. Tibet continued as a Central Asian empire until the mid-9th century, when a civil war over succession led to the collapse of imperial Tibet. The period that followed is known traditionally as the Era of Fragmentation, when political control over Tibet became divided between regional warlords and tribes with no dominant centralized authority. Question: What was divided between warlords and tribes with no dominant centralized authority?
A:
political control over Tibet