Manuscript culture seems to have really begun around the 10th century. This is not to say however, that manuscripts and the recording of information was not important prior to the 10th century, but that during the 10th century, historians see an influx and heavier weight placed on these manuscripts. This was a time when medical practitioners were advancing what they knew about the human body and the way that certain substances interacted with it. These medical practitioners recorded this information and passed it on through the means of literate people. Catholic monasteries and cathedrals during the Middle Ages were centers of learning (see cathedral schools), so it would only make sense for these texts to end up in the hands of the monks.