The modern iteration of Ghetto Nightmare is around since about age 51, when the then monarch picked the name because he liked it. The banner came within a week after that. So we can't claim the mantle of longest kingdom. My memory is not particularly reliable, but I do know that the name was chosen shortly after I joined. I just can't remember exactly when that was.

I would suspect it's Dungeon Dwellers that have been around the longest? But I'm not sure. I'd love to someday hear the story behind Knights of Erin.