During the 10th century, two major changes came to the land of the Franks. They were unconnected, but each contributed in its own way to the establishment of medieval feudalism. The first was a set of inheritance reforms, the second…the Normans.
The first monastery in France was in Tours, established by St. Martin in the 5th century. Monasticism was not a widespread movement at first, but by the time of the Carolingians, the kings were donating land to build some early Benedictine houses. Although there were other monastic traditions in Syria and Egypt, the Order of St. Benedict was the only option in Rome’s region of influence. The Rule of St. Benedict gave rules for how to live in this new lifestyle. They were to live in poverty under the authority of an abbot (from Aramaic “father”) in obedience, humility and prayer.
By the 900s, there were many more Benedictine monasteries. This was all well and good, but it created an inheritance problem. In the Frankish Salic Law, the landowner could divide as he chose, in theory among his sons, but actually among anyone. Many landowners willed away large sections of their land to the local monastery in exchange for perpetual prayers. They left much land to their sons, but it was diminished in size overall. Each son received an estate that was far inferior to his father’s. Each often repeated the process when he grew old, leaving even smaller estates to the grandsons.
However, these pious dying Franks had been part of a Military-Agricultural Complex. The Carolingian dynasty depended on each subdivision of land to support horses and armed men. It was how the army was raised; each lord was responsible for mustering (and training) a certain number of both. He then sent a required number of mounted knights to the regional lord, who led them against the king’s enemies. But now, estates were being whittled away from within by non-taxable church ownership. After a few generations of piety, there might be barely enough land left to support the barony’s required horse-breeding, iron-smelting, and weapons-training. The monasteries had no obligation to send fighting men or raise horses, though they could certainly raise and sell them for income.
By the 11th century, the French kings forced inheritance reform: a man’s land had to pass to his oldest male heir in one piece. It was unfair to the younger sons, but it was much better for the people who lived under them. The law also put a top limit on how much land could be donated to monasteries.
Alliances became more stable and boundaries stopped changing with every generation. Primogeniture became the first line of defense in the ongoing war against Eastern invaders. In later times, social reformers pointed out how primogeniture kept all the wealth in the hands of a few. The Carolingian kings might rejoin: “You say that like it’s a bad thing.” Primogeniture created the feudal system as we see it in the Middle Ages, when younger sons went out as landless knights to win their own manors while the older brothers ruled in a pyramid of power.