Pietro De Crescenzi

Knowledge of proper agricultural techniques waned in the thousand years following the fall of Rome, except in monasteries, where texts on soil and crop management were preserved and studied. Into this setting, in the 13th century, came a Bolognese jurist named Pietro De Crescenzi.

De Crescenzi (c.1230 - c.1320) practiced as a layer from 1274 until 1300, during which time he traveled from city to city in the Lombard League. Traveling jurists were important, due to the concern that local lawyers would not be impartial. As he traveled, he took note of farming practices, comparing them to what he observed at the Dominican monastery in Bologna (his brother and several friends were members there, and its head was his confidant).

He retired at the age of 70 in c.1300 to his own farm in a suburb of Bologna. His application of efficient farming practices earned him such a reputation that King Charles II of Sicily asked him to write a treatise on the subject.

De Crescenzi produced the Liber ruralium commodorum ("Book of rural benefits") between 1304 and 1309, dedicated to Charles. It was so well received that Charles V of France ordered a French version in 1371. It was translated into Latin in 1471; 57 editions in different languages followed.

This was the first serious work on agronomy in a millennium, and borrowed heavily from the "lost" classical works on the subject. The structure is based on the De re rustica ("About rural things") of the 1st century Roman writer Columella, and De Crescenzi was clearly able to get a copy of the agricultural work of another Roman, Taurus Palladius, but he makes his own point in the introduction about soil that is fundamental to all farming:

The power of the soil should be investigated, and when it is discovered it is like an inestimable treasure that should be conserved with humility and patience.

He argued that a field giving poor yields should be left alone for four or five years until planted again. He recognized the need for crop rotation, "green manure" by plowing under what was growing wild, and regular fertilization—practices that make sense to us today, but that had fallen out of use for centuries.

The work is in 12 parts:

1. Siting and layout of a manor, villa or farm, considering climate, winds, and water supply; also the duties of the head of the estate
2. Botanical properties of plants and horticultural techniques
3. Agriculture of cereals and building of a granary
4. Vines and winemaking
5. Arboriculture—trees useful for food and medicine
6. Horticulture—plants useful for food and medicine
7. Management of meadows and woodland
8. Pleasure gardens
9. Animal husbandry and bee keeping
10. Hunting and fishing
11. General summary
12. Monthly calendar of tasks

You can see how extensive and thorough a guide for farming on a large and a household scale it is.

One of his emphases is on the utility of a particular plant, so I thought we'd talk next about its history and about what De Crescenzi has to say about it: the misnamed lupine.

Medieval Agronomy

It occurs to me that, in order to explain the importance of Pietro De Crescenzi, I should explain the thousand years that preceded him.

With the fall of Rome and barbarian invasions, farming started to suffer. That may be an unexpected statement, but there were reasons. With the loss of the Pax Romana ("Roman Peace"; formally, it refers to a 200-year span that ended in 180CE, but its influence lasted longer), invasions led many rural communities to migrate to cities for safety. Farmers who remained outside cities were focused on safety and managing their land with perhaps fewer farmhands. Marching armies devastated the arable land.

Roman irrigation systems were not maintained, both those that brought water to where it was needed and those that drained water from lowlands. Italy became increasingly swampy and a breeding ground for malaria, driving farming into smaller hilly areas where fields were overworked and erosion was more likely.

Classical Rome understood about erosion and soil management—Cato and Vergil had written about farming, and there was an expert named Taurus Palladius who wrote definitive Roman works on agronomy in the 5th century—but as civilization faltered, so did education and the knowledge of efficient agricultural practices. 

The Moorish lands maintained good practices, but Western Europe did not know about them, except in one area. Knowledge of the writings of Palladius and Mago the Carthaginian (whose 28 books written in Punic are lost, but we have Greek and Latin fragments) could be found in the enclaves that valued and collected and copied books: the monasteries. Monasteries in the Middle Ages maintained model farms, with the resources, knowledge, and manpower to get the most from the land without exploiting it.

In fact, it was the observation of farming techniques throughout Lombardy, and especially how monasteries managed their land differently, that got a jurist from Bologna thinking about agriculture. Although an expert in law with a reputation for fairness and legal knowledge, he started to take an interest in the differences he saw in farming techniques. When he retired to Bologna in his 70s, he decided to do something about what he had observed.

Tomorrow, we will see how this retired lawyer kick-started modern agronomy, the science of soil production and crop management.