Final answer:
A medieval king would likely fortify his castle as a first line of defense against invaders, including structures like moats and stone walls, and adapt designs to defend against artillery.
Step-by-step explanation:
A medieval king would most likely want to fortify his castle to defend against invaders. The term 'entrench' implies digging trenches around a position which can be considered a part of fortifying, while 'enmesh' doesn't directly relate to defensive structures. Fortifications of a castle would include moats, thick stone walls, and in later eras, earthen banks to support walls against cannon fire. These defenses served as the first line of defense to protect the inhabitants and prevent enemies from successfully laying siege. The star-shaped fortresses arose to adapt to the changes in military technology, such as the use of cannon, allowing defenders to aim in all directions and improve overall defensive capabilities.