Context:

Referred to as 'a wonderful book' about John Hawkwood's company rampaging across Tuscany and Northern Italy. The exact title is not mentioned but is described in the context of discussing free companies and mercenaries moving to Italy after the Treaty of Bretigny.

Context:

Explicitly mentioned as a book - described as 'Sir Arthur Conan Doyle's masterwork' and 'the book that fired your love of history' for Tom Holland. Passages from the book are read aloud at the beginning and end of the episode, depicting scenes from the Battle of Poitiers.