Complex sentence: In the context of the French Revolution, a Jacobin originally meant a member of the Jacobin Club (1789-1794), but even at that time, the term "Jacobins" had been popularly applied to all promulgators of revolutionary opinions.
Split into simpler sentences: In the context of the French Revolution, a Jacobin was a member of the Jacobin Club (1789--1794). At that time, the term was popularly applied to all promulgators of revolutionary opinions.