Castles were built primarily as fortified structures for protection and defense. They served as military strongholds to defend against rival lords, invaders, and potential rebellions. Castles also allowed the lord or nobility living there to control and administer the surrounding land, serving as centers of local government, justice, and administration. Additionally, castles were symbols of power, prestige, and wealth, often demonstrating the status of the lord or royalty residing within. Over time, castle designs evolved from simple wooden fortifications to complex stone structures with thicker walls, towers, and other defensive features to improve security and durability.

More specifically, castles:

• Protected inhabitants from external threats and invasions.
• Housed the lord, their family, servants, and soldiers.
• Provided a military base to exert control over the nearby region.
• Served as administrative centers and places to hold court.
• Acted as a visible symbol of authority and control in the medieval landscape.

The strategic location was pivotal, and building castles sometimes required royal permission, highlighting their political role as much as their military function. They often influenced the growth and structure of nearby settlements due to the safety and economic opportunities they offered.

In essence, castles were multifunctional fortifications blending defense, governance, residence, and representation of power in medieval society.