The Tang dynasty, seen by many historians as a glittering peak in China's history, was brought to its knees by shifts in the monsoon cycle, according to a study.
Famed for a flowering of art and literature and for prosperity brought by trade with India and the Middle East, the dynasty spanned nearly three centuries, from AD 618 to 907, before it was overwhelmed by revolt.
Scientists led by Gerald Haug of the Geoforschungszentrum (GFZ) in Potsdam, eastern Germany, looked at sedimentary cores taken from a lake at Zhanjiang in coastal southeastern China, opposite the tropical island of Hainan.
The timing seems roughly coincident with the period just before the beginning of the Medieval Warm Period.