Giving just enough background knowledge

I’ve just started the third novel in my series The Lost King which tells the story of the boy who was proclaimed king in 1066 and lost his throne to William the Conqueror.

I am currently grappling with the problem of starting the story with sufficient background for any new reader who happens to find this book before the earlier ones.  At the same time, I need to remind readers of the series about what has happened so far.  The challenge is to do this without boring them or writing things which they well remember and don’t need to be emphasised.

I’ve hit on one notion which seems to be working.  However, I need to take a long hard look at this and make sure that it works exactly how I want for all the purposes I need.

The life of a writer is never dull.