The powerful Earl of Léonas was one of the loyalist nobles to the king and as a reward had given the Earl vast lands. In return for the land the Earl was charged with keeping the kings peace in the area.
The Earl relied on nobles like Baron Hreaðemús, equally as loyal to both king and their overlords, in keeping peace and sending much needed reinforcements to the king fighting his war on the continent. The Baron had help serve the king and Earl in both international and local conflict and had been reward as tenant of Cwelderæde Castle.
Whilst the castle wasn’t large it was well protected being located in a lake with the only access via the drawbridge. The Baron was satisfied with the castle and continued to serve both the Earl and his King.
I used Hever castle as inspiration Hever Castle
. Though it dosen't look anything like it!