Complex sentence: Previously, the Tidal Handicap had been run at Aqueduct Racetrack and records show that a Tidal Stakes was run at the old Sheepshead Bay Race Track for almost thirty years from the 1880s through until the track closed in 1910.
Split into simpler sentences: Previously, the Tidal Handicap had been run at Aqueduct Racetrack. The Tidal Stakes was run at the old Sheepshead Bay Race Track for almost thirty years from the 1880s through until the track closed in 1910.