In fortification architecture, a rampart is a length of embankment or wall forming part of the defensive boundary of a castle, hillfort, settlement or other fortified site.
After the fall of the Western Roman Empire, there was a return to the widespread use of earthwork ramparts which lasted well into the 11th century, an example is the Norman motte and bailey castle.
As castle technology evolved during the Middle Ages and Early Modern times, ramparts continued to form part of the defences, but now they tended to consist of thick walls with crenellated parapets.
[5] In the first half of the 16th century, the solid masonry walls began to be replaced by earthen banks, sometimes faced with stone, which were better able to withstand the impact of shot; the earth being obtained from the ditch which was dug in front of the rampart.
At the same time, the plan or "trace" of these ramparts began to be formed into angular projections called bastions which allowed the guns mounted on them to create zones of interlocking fire.