Complex sentence: During the early years of the American period, the gaol served as a stable for horses competing at the "hipódromo" (racetrack) nearby, but it was eventually used once again as a prison, both for the city and the province.
Split into simpler sentences: During the early years of the American period, the "Carcel" served as a stable for horses competing in the "Hipódromo" nearby. But it was eventually used once again as a prison, both for the city and the province.