Complex sentence: Beginning in 1906, Charlotte Berend-Corinth showed her paintings at the Berliner Secession, and she joined the Secession in 1912 and did not leave it after the separation of the new Freie Secession led by Max Liebermann when Lovis Corinth became the new head of it.
Split into simpler sentences: Beginning in 1906, Charlotte Berend-Corinth showed her paintings at the Berliner Secession. She joined the Secession in 1912 and did not leave it after the separation of the new Freie Secession led by Max Liebermann when Lovis Corinth became the new head of it.