Complex sentence: Lucy Duff Gordon's connection to her design empire began to disintegrate following a restructuring of Lucile, Ltd in 1918--19, and by September 1922 she had ceased designing for the company, which gradually diminished in success after her departure.
Split into simpler sentences: Lucy Duff Gordon's connection to her design empire began to disintegrate following a restructuring of Lucile, Ltd in 1918--19. By September 1922 she had ceased designing for the company, which gradually diminished in success after her departure.