Complex sentence: Key members of the seven were linked with the Qingtan school of Daoism as it existed in the Cao Wei state (or nation); they found their lives to be in danger when the avowedly "Confucian" Jin Dynasty (Sima clan) came to power.
Split into simpler sentences: Key members of the seven were linked with the Qingtan school of Daoism as it existed in the Cao Wei state (or nation). The Seven Sages found their lives to be in danger when the avowedly "Confucian" Jin Dynasty (Sima clan) came to power.