I'm so glad to follow you on your trip to Beeston Castle, although I read it very slowly.
Here I have a question. Since the information shows that King John was born in 1166 and died in 1216, how to understand the sentences:

As early as the 1220s Ranulf, Earl of Chester was charged with building Beeston Castle by King John...and The earliest parts of the hillfort were built in 1220 by the Earl...

It means that it is King John who appointed Earl of Chester to build Beeston Castle in the 1220's(1210-1216), but it was actually built in 1220 just after his death, ok？
Oh, I'm trying to learn the history of English with great interest via your writing and I enjoy your vivid description about the hillfort a lot. I have also learned a new word: portcullis which reminds me of the heavy iron gate of prison.

Another question is

...for extra soldiery to help defend the city of Chester from any attack from rebellious Nobels.

What do Nobels mean？
Thanks for allowing me to join your journey again. It is such a huge bless for me to have such a wonderful guide. You have no idea how charming your words could be! It seems that England and its history is so close to me.