Complex sentence: At the age of 22, he moved to Paris and three years later, he began designing for the House of Cristobal Balenciaga for three years before quitting to work for Courrèges.
Split into simpler sentences: At the age of 22, he moved to Paris. Three years later he began designing for the House of Cristobal Balenciaga for three years before quitting to work for Courrèges.