 With this letter , Dost Mohammad formally set the stage for British intervention in Afghanistan. At the heart of the Great Game lay the willingness of Britain and Russia to subdue, subvert, or subjugate the small independent states that lay between Russia and British India .
<clarity>  With this letter , Dost Mohammad formally set the stage for British intervention in Afghanistan. At the heart of the Great Game lay the willingness of Britain and Russia to subdue, subvert, or subjugate the small independent states that lay between Russia and British India .
 The letter marked the beginning of British influence in Afghanistan, and the subsequent Anglo-Russian struggle known as the Great Game lay the willingness of Britain and Russia to subdue, subvert, or subjugate the small independent states that lay between Russia and British India .