‘Greenmantle’ is John Buchan’s second novel featuring Richard Hannay. There were two Hannay novels set during the First World War, ‘Greenmantle’ published in 1916 and ‘Mr Standfast’, published in 1919. ‘The Thirty-Nine Steps’ perhaps the best known of all five Hannay novels, was published in 1915 and covers a period leading up to the conflict.
‘Greenmantle’ is set in Constantinople during November 1915. Hannay is called in to the Foreign Office by Sir Walter Bullivant, who he first met in ‘The Thirty-Nine Steps’. There are rumours of an uprising in Turkey. Hannay travels through enemy territory to meet up with his friend Sandy. Together they undermine Germans' plans to use religion as a weapon of war, their efforts then lead to the battle of Erzurum.