I've been watching a Netflix series recently called 'World Without End'. It's very well done and represents, more or less, the early years of King Edward III's reign (1327-1377) as seen through events in the (fictional) town of 'Kingsbridge', and in London and on the battlefields of France.
I highly recommend it.
A few years back my brother sent me a link to this video which explains the difference between the United Kingdom, Great Britain, and England.
Hold onto your hats ! (It's so fast you have to listen very carefully!