As protection from raiding elephants.
The water-filled trench around a castle is called a moat.
Mr. Wemmick lives in a small replica of a castle in Walworth.
I think that the 'trench' you are thinking of is a moat. You could say that it is a trench full of water that surrounds the castle. If you are not thinking of a moat then I am sorry.
A moat surrounded the castle.The moat was a form of defence for castles.
the old french & medieval latin words for a mound or fortified height shifted in Norman french from the castle mound to the ditch dug around it before entering English around 1362
Into the Moat was created in 2001.
Advantage of a water moat
Ryan Moat's birth name is James Ryan Moat.
The moat cleaners. ;)
A wide moat, high walls with several bastions on the corners and within, a fortified tower or donjon (today called the White Tower) where defenders could retreat to if the walls had been broken through.Today the moat has been drained. Due to a less-than-perfectly made connection with the river Thames, the water in the moat wasn't regularly flushed by the river's tide as intended but remained largely stagnant, which made it over time stink to high heaven.
The moat is filled with sharks