As they are "medieval" castled, they were built to dominate the land in "medieval" times - that is in the Middle Ages, a period of European history encompassing the 5th to the 15th centuries, from the collapse of the Roman Empire to the beginning of the Renaissance.
Medieval castles.
There is nothing different between todays castles and medieval time castles. Today's castles were built in medieval times.
The welsh medieval castles were big and gray.
Medieval castles were built by local lords who ruled the area. They owned the land, collected taxes and dispensed 'justice'. They required castles to protect themselves from unhappy locals, and sometimes from foreign invaders (depending on the country), and to display their power.
Medieval times
around about 1100 to defend their land against raiders and other enemies
in the late medieval period many medieval castles did have a primitive type of cannon.
Castles were invented in medieval times.
There are no genuine medieval castles in the USA, because the Americas were not discovered until after the medieval period had ended. There are the "fairytale" Disney castles and some modern attempts at reconstructing medieval castles, but no genuine ones.
Who is most important in medieval history - kings and emperors. Where do they live - in castles.
Ottonian castles look like Medieval palaces that tower over the rest of the land. They were often built on hills or the tops of mountains and made of stone.
Motte and bailey castles, Stone keep castles and Concentric castles