Chess tournament
In 1851, Adolf Anderssen became first unofficial champion. In 1858, Paul Morphy beat him and became second unofficial champion. In 1871, Johannez Zukertort defeated Adolf Anderssen to become third unofficial chess champion. There are three unofficial world chess champions: Adolf Anderssen, Paul Morphy and Johannes Zukertort, stemming from first strong international tournament in London in 1851, won by Anderssen.