Complex sentence: Minamoto no Yoshitomo (1123--1180), was killed in a campaign to overthrow the imperial chancellor, Taira no Kiyomori; and his wife, Tokiwa Gozen was compelled to flee Kyoto with her three sons.
Split into simpler sentences: Minamoto no Yoshitomo (1123--1180), was killed in a campaign to overthrow the imperial chancellor, Taira no Kiyomori. Yoshitomo's wife, Tokiwa Gozen was compelled to flee Kyoto with her three sons.