Complex sentence: Emperor Shirakawa (白河天皇) was the 72th imperial ruler of Japan and the first to ostensibly retire to a monastery, but in fact to continue to exert influence over his successor.
Split into simpler sentences: Emperor Shirakawa (白河天皇) was the 72th imperial ruler of Japan. He was the first to ostensibly retire to a monastery, but in fact to continue to exert influence over his successor.