Medieval castles are often portrayed in modern literature as beautiful buildings belonging to brave leaders, but the truth is much darker. In many cases, kings and lords built the giant structures, not to protect local populations, but to dominate the masses and collect money from them. And so, for hundreds of years, castles stood as instruments of conquest. This was particularly true from the 10th to the 15th centuries. In what ways did castles help nobles dominate and govern entire societies?   Castles Were Used to Seize Territory and Suppress Rebellion Image from the Bayeux Tapestry showing William with his half-brothers. William is in the center, Odo is on the left with empty hands, and Robert is on the right with a sword in his hand. Source: Wikipedia   Medieval castles offered much more than simple refuge to soldiers in times of war. The enormous buildings were regularly used to dominate subjects in the areas in which they were built and derive revenue from them through taxes. The story of the Norman Conquest of 1066 illustrates the situation clearly, as right after their victory, the Normans went on a building spree and built roughly 600 to 800 castles across England by the 12th century.   William the Conqueror, in particular, handed out land in a calculated pattern so that one royal castle was, in many cases, within a day’s march (roughly 15 to 20 miles) of the next. The spacing pattern helped to suppress rebellion among the defeated Anglo-Saxons.   They Were Used as Toll Collection Centers The Rhine in Basel, Switzerland. Source: Wikipedia   Once the fighting died down and trading resumed, the towering medieval castles of Europe ceased being just fortresses. They were converted into revenue collection points by the lords who controlled them. As a result, many nobles built their castles right on the busiest roads and rivers so that merchants had no other choice but to pay up if they wanted to use the routes. Nowhere was this more obvious than along the Rhine. By the early 1300s, more than 60 castles lined its riverbanks, each one basically a medieval toll booth. A trader heading from Basel to Cologne would, for example, be compelled to pay between 10 to 25 percent of his cargo’s worth, just in fees.    That said, things in England worked a bit differently. Because most towns grew under the protection of a castle or a major church, locals paid steady market tolls and rent to the lords.    They Were an Immense Economic Burden Beaumaris Castle, Anglesey, UK. Source: Wikimedia Commons   The process of building castles required total domination of territories in which they were to be built in order to obtain cheap labor for construction. Unfortunately, the procedure also stripped the land of its resources such as timber and stone. King Edward I of England revealed just how expensive such endeavors were when he launched his final conquest of Wales in the late 13th century.   Beaumaris Castle alone, which was constructed in 1295, took thousands of laborers to build. It utilized about 400 skilled masons and over 2,000 laborers at peak periods, most of whom were paid wages, though some were compelled to work under wartime labor obligations. It is estimated that Edward spent roughly £80,000 to £100,000 on his ring of Welsh castles and associated fortifications between 1277 and 1330. The sum, spread over more than five decades, placed a heavy burden on the royal treasury as the average annual revenue during that period was about £20,000.   They Were Used as Centers of Justice Beaumaris Castle Inner Ward. Source: Cadw   Castles stood as important centers of administration in many regions during the medieval years and acted as hubs where lords managed their estates and enforced local laws. Established lords, especially from the 11th century to the 13th century, held special rights called high justice in many places across Europe. The rights allowed them to dispense punishments to lawbreakers for breaking local laws, and even order executions. Hanging was a regular punishment in many regions at the time, but over the years, kings started to take more control, especially from the 14th century onward. They also started to gain greater influence over local justice systems through royal courts.   Towering Symbols of Fear and Royal Control The Norman White Tower, the keep of the Tower of London, overlooking the River Thames. Source: Wikipedia   Almost every medieval castle was an unmistakable symbol of the royal authority that held power over the lives of ordinary people. King Henry II of England made this point unmistakably clear in the 1180s when he commissioned the building of the massive Great Keep at Dover Castle – a towering castle that was visible for miles across the English Channel. Later kings recognized the danger of having too many private towering fortresses and introduced the License to Crenellate (from roughly 1200 to 1500). The royal permit meant that no noble could build or fortify a castle without the crown’s explicit, written approval.