This beautiful illustration of Little Cullen from Rosemary Sutcliff’s novel, The Silver Branch is from The Folio Society’s 2004 edition, drawn by Roman Pisarev. (From another great comment from Anne ).

You can buy this beautiful edition of the book  from the Folio Society’s website. There is also a stunning version of The Eagle of the Ninth, probably Rosemary Sutcliff’s most famous novel which you can buy it here.