...In A Study in Scarlet it says that Dr. Watson was wounded at the Battle of Maiwand. This was a setback suffered by the British Army during the Second Afghan War in 1880. Conan Doyle was an arch-imperialist and was well known for his vocal support for the consolidation and expansion of the Empire. It is therefore not at all surprising that he should use this imperial reference. It would have been well known by nearly all of his reading public.