A flag can show one of two things:
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 times
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.
A castles weakness is the bridge, flags, and other things unknown.
Who is most important in medieval history - kings and emperors. Where do they live - in castles.
mote and bailey castles and stone keep castles and Concentric Castles
medieval Europe
Life