Complex sentence: After Falk's passing, King Features Syndicate collaborated with the European comics publisher "Egmont", which went from initially publishing Phantom stories in licensed comic books to providing the stories for the newspaper strip by adapting their comic-book stories.
Split into simpler sentences: After Falk's passing, King Features Syndicate collaborated with the European comics publisher "Egmont" on the strip. They went from initially publishing Phantom stories in licensed comic books to providing the stories for the newspaper strip by adapting their own comic-book stories.