Complex sentence: His mother Bessie Rayner Parkes (1829--1925) was a writer, activist, and a major force in efforts to gain greater equality for women, being a co-founder of the "English Woman's Journal" and the Langham Place Group.
Split into simpler sentences: His mother Bessie Rayner Parkes (1829--1925) was a woman of many talents, both as a writer and as an activist. She was a major force in efforts to gain greater equality for women, being a co-founder of the "English Woman's Journal" and the Langham Place Group.