Complex sentence: It was amid the New Woman and burgeoning suffragist movement that, in 1908, O'Neill began to concentrate on producing original artwork, and it was during this period that she created the whimsical Kewpie characters for which she became known.
Split into simpler sentences: It was amid the New Woman and burgeoning suffragist movement that, in 1908, O'Neill began to concentrate on producing original artwork. During this period that she created the whimsical Kewpie characters for which she became known.