"It seems unreasonable to call a fighter that nobody has ever heard of "the greatest" as the initial post suggests."
But pdq, I qualified that as "pound for pound". Langford was a natural middleweight fighting as a heavy. There is also a difference between forgotten and never heard of. If you read my link in its entirity you will see that he was a hall of famer, maybe forgotten but certainly not unknown. A subjective call on my part for sure, but not without statistics to back it up!