Although the title "World's Greatest Athlete " seems a natural fit for these two events, its traditional association with the decathlon/heptathlon officially began with Jim Thorpe . During the 1912 Olympics in Stockholm, Sweden, Thorpe won the gold medal in the Decathlon (among others). Thorpe notably also competed professionally in soccer , baseball , American Football , and basketball ; and competed collegiately in track and field , soccer , baseball , lacrosse , and did ballroom dancing . King Gustav V of Sweden , while awarding Thorpe the decathlon gold said: "You, sir, are the greatest athlete in the world." That title has become associated with the decathlon event ever since.