Several innovations occurred to organs in the Middle Ages, such as the creation of the portative and the positive organ. The portative organs were small and created for secular use and made of light weight delicate materials that would have been easy for one individual to transport and play on their own. The portative organ was a "flue-piped keyboard instrument, played with one hand while the other operated the bellows." Its portability made the portative useful for the accompaniment of both sacred and secular music in a variety of settings. The positive organ was larger than the portative organ but was still small enough to be portable and used in a variety of settings like the portative organ. Towards the middle of the 13th century, the portatives represented in the miniatures of illuminated manuscripts appear to have real keyboards with balanced keys, as in the Cantigas de Santa Maria.