Some of my fellow Sherlockians have recently written a series of emails about the battle of Maiwand, in which Watson was so badly wounded he was sent home and eventually met Holmes.
I first began to take an interest in this iconic pair eleven years ago - when I saw a modest memorial in Beverley Minster  to a group of men who died marching up from Quetta to relieve Kandahar, under siege by the victorious Afghans, at the same time as Major-General Frederick Roberts was bringing a similar force from Kabul.
The famous painting of the Last Stand of the 66 Regiment of Foot, showing Bobbie (the Regimental Mascot) standing calmly in the middle of the carnage, can be found in Colonel Leigh Maxwell's book My God! Maiwand  first published by Leo Cooper in 1979. It also appears in what must be the definitive account of the battle by Richard J. Stacpoole-Ryding in association with the Rifles (Berkshire and Wiltshire) Museum: MAIWAND The Last Stand of the 66th (Berkshire) Regiment in Afghanistan, 1880, published in 2008 by The History Press.
My own book, In Search of Doctor Watson, written soon after my visit to Yorkshire but not published until 2011, has an account of the battle of Maiwand and some speculations about who may have been the original Model for John H. Watson - which I hope you will find interesting.