Complex sentence: He became a member of the revolutionary expressionist group "Die Brücke" (The Bridge), of Dresden, in 1906, upon the group's invitation; this association lasted only until the end of the following year.
Split into simpler sentences: He became a member of the revolutionary expressionist group "Die Brücke" (The Bridge), of Dresden, in 1906, upon the group's invitation. This association lasted only until the end of the following year.