Keres was an Estonian chess grandmaster, and a renowned chess writer.
He was among the world's top players from the mid-1930s to the
mid-1960s. When the Iron Curtain came down in 1992 Estonia immediately printed currency and honored Keres by putting him on their 5 Krooni note. In 2016 The European Union allowed Estonia to Design the 2 Euro coin and they again honored their hero by putting him on the obverse. These are the only two instances where a chess player appears on world money.
narrowly missed a chance at a world championship match on five
occasions. He won the 1938 AVRO tournament, which led to negotiations
for a title match against champion Alexander Alekhine, but the match
never took place due to World War II. After the war Keres was runner-up
in the Candidates' Tournament on four consecutive occasions. Due
to these and other strong results, many chess historians consider Keres
the strongest player never to become world champion and one of the
greatest players in history. He was nicknamed Paul the Second, The
Eternal Second and The Crown Prince of Chess.