Answer:
They were asked to help the Ming defend against the rebels.
Explanation:
Li Zicheng who was a former Ming official became the leader of the peasant rebels and he proclaimed the Shun dynasty which was short-lived.
When Li Zicheng moved against the Mings, the Ming general Wu Sangui went into allegiance with the Qing. The Manchu prince, Dorgon and Wu Sangui joined forces together to defeat him at the Battle of Shanhai Pass.
So, Manchu became involved in China’s peasant uprising when they came to help Ming against the rebels.
