Complex sentence: Under the main roof is a 16th century chapel which was sponsored by Vasco de Quiroga, for indigenous mine workers called the Templo de los Hospitales (Temple of the Hospitals).
Split into simpler sentences: Under the main roof is a 16th century chapel that was sponsored by Vasco de Quiroga for indigenous mine workers. It's called the "Templo de los Hospitales" (Temple of the Hospitals).