Complex sentence: Gosden has trained the winners of over 100 Group 1 races in the United States, Europe, the Middle East and Asia, and is generally considered one of the finest and most successful racehorse trainers of his generation.
Split into simpler sentences: Gosden has trained the winners of over 100 Group 1 races in the United States, Europe, the Middle East and Asia. He is generally considered one of the finest and most successful racehorse trainers of his generation.