Howard Hill is a legend because he is one of the all time best archers ever to have walked the planet. Howard Hill has won over 190 arching World Championships which no other archer has even been capable of doing. He is mainly known for his roll in the movie Adventures of Robin Hood, but to this day is still considered the best archers of all time.
Archery isn't what it used to be. Sad, but true. Fortunately, a few men qualify as legends in this arena. Howard Hill's championship record (still unmatched) alone qualifies him for this status; however, his kill record is much more impressive. They fact that he used a long bow makes it even more so.
Perhaps only to a certain niche, but still a legend.
If you ask me, Howard Hill is pretty irrelevant. No one really cares about archery anymore and he is not a legend in my eyes. A legend is someone who is really impressive and leaves a huge legacy and Howard Hill did not do this. Most people would ask Howard Hill who?