Monastic medicine and the Garden of Simples

In the Middle Ages the plants cultivated were used for the composition of simple medicines, that is to say they were made using either a single plant or a combination of different types.
The tradition continued and was expanded in the Middle Ages with the creation of Hortus simpliciumor Hortus medicus (also called a viridarium in the early Middle Ages). The hortus simplicium (for the cultivation of plants to make "simple" medicines, and thus referred to as a Garden of Simples), was developed in monasteries and convents.
One of the first was founded by Cassiodorus, a former advisor to the Emperor Theodoricus, who retired from the political life on the fall of the Roman Empire.
Interested by medicine, he wrote the Istitutiones divinarum et humanorum, in which he advised monks to cultivate medicinal plants and to study, transcribe and illuminate the sources of the past, such as Hippocrates, Dioscorides and Galen.
The cultural and health-related work performed by the monastic orders was fundamental. They occupied themselves with helping the sick, as their vocation called upon them to do. Having access to Classical sources, they all studied pharmaceutics and produced medicines of great efficacy. The monks produced descriptive guides called Hortuli to all the plants they cultivated and used.

Hortuli were sets of plant illustrations in which were described the characteristics and virtues of each plant. They helped spread awareness of medicine and the use of officinal plants rapidly between monastic orders. Guesthouses and hospitals were built next to the abbeys to welcome sick pilgrims, until in 1200 when Pope Honorius III prohibited secular clerics to practise medicine and in 1231 Frederick II of Svevia banned all relations between the profession of the apothecary and that of the doctor, thus preventing anyone to exercise the medical profession without authorisation.
The only public cultural centre able to confer the title of doctor was the Medical School of Salerno. Probably originally linked to a monastic centre, it was at the Salerno school that elements of the Classical tradition influenced by the Arab culture made their presence felt on Western medicine.