There are 2 books in the The Middle Ages series. The newest book is The Hundred Years War which came out in 2017.

2
The Hundred Years War

Book cover of The Hundred Years War: Volume 4: Cursed Kings
Jonathan Sumption's Cursed Kings is the eagerly anticipated fourth volume in what Allan Massie has called "one of the great historical works of our time." Cursed Kings tells the story of the destruction of France by the madness of its king and the greed and violence of his family. In…