History Lesson on England... Britain?

Our history lesson today was on the "Middle Ages", or the "Dark Ages" in Britain/England/Ireland/Scotland.  We sort of learned the difference between Britain and England, but I am still confused.  England is everything BUT Whales, Scotland and Ireland?  Is Britain all?  We learned about the Celts, the Anglo-Saxons and the story of Beowulf.  We are also having fun reading stories from Celtic Fairy Tales and Celtic Memories. Here they are in their cloaks with their brass dragon brooches.  After our history lesson they ran around in their cloaks playing Harry Potter.  I guess that's what they associate with England and cloaks.  (Notice Sylvia's wand.)