Original:  It  was founded by Koxinga (Zheng Chenggong) as part of the loyalist movement to restore the Ming dynasty on the Chinese mainland after its rump state in  southern China was overthrown by the Manchu-led Qing dynasty.
Revised:  At its peak the kingdom's maritime power dominated varying extents of coastal regions of southeastern China, and its vast trade network stretching from Japan to Southeast Asia. was founded by Koxinga (Zheng Chenggong) as part of the loyalist movement to restore the Ming dynasty on the Chinese mainland after its rump state in southern China was overthrown by the Manchu-led Qing dynasty.
Edit intent: meaning-changed