I'm working on a MG novel set in a 14th-century English village. My 10-year-old main character would know very little about the larger world in which she lives, nor would most other villagers care about things beyond the village. I've mentioned that Edward Longshanks is king, to provide context, but nothing other than that. I could provide it in an author's note, but to me, it would seem artificial to work it into the main text.
How important is it for readers to have the bigger picture? (I like how we know, in Cushman's Catherine, Called Birdy, that the MC's uncle is a crusader, or in Avi's Crispin, that John Ball is at work. But those things figure into the plots, and nothing like that works in my novel.)