This group photo was taken 65 years after the Battle of Waterloo, which ended the Napoleonic Wars. Four of the men shown here fought in the battle. The fifth also fought against Napoleon but he was not present at the final battle. I am sure he got a lot of teasing from his fellow veterans.
The men were photographed at the Chelsea Hospital in 1880 were presumably they were being cared for in a sort of Victorian old folks' home for retired soldiers. When the photo was taken, they were all in their 80s and 90s so it is safe to assume that this is a photograph of some of the last surviving veterans from that era.