Complex sentence: Southern Image was best known for his wins in the grade one Pimlico Special and the grade one Santa Anita Handicap he is the only horse ever to win both prestigous races on seperate coast of the United States.
Split into simpler sentences: Southern Image was best known for his wins in the grade one Pimlico Special and the grade one Santa Anita Handicap. He is the only horse ever to have won both prestigous races on seperate coast of the United States.