Complex sentence: Against this hopeless backdrop, the penultimate sovereign of Tang, Zhaozong 昭宗, ascended the throne in 888, and although a man of lofty ambition, he remained throughout his reign a mere puppet in the machinations of court politics.
Split into simpler sentences: Against this hopeless background, the penultimate sovereign of Tang, Zhaozong 昭宗, ascended the throne in 888. Although a man of lofty ambition, Zhaozong remained throughout his reign a puppet in the machinations of court politics.