World Series of Poker
The World Series of Poker (WSOP) is a series of poker tournaments held annually in Las Vegas and, since 2005, sponsored by Caesars Entertainment Corporation (known as Harrah's Entertainment until 2010). It dates its origins to 1970, when Benny Binion invited seven of the best-known poker players to the Horseshoe Casino for a single tournament, with a set start and stop time, and a winner determined by a secret ballot of the seven players.
Poker
In the 1937 edition of Foster's Complete Hoyle, R. F. Foster wrote: "the game of poker, as first played in the United States, five cards to each player from a twenty-card pack, is undoubtedly the Persian game of As-Nas." By the 1990s some gaming historians including David Parlett started to challenge the notion that poker is a direct derivative of As-Nas. Developments in the 1970s led to poker becoming far more popular than it was before. Modern tournament play became popular in American casinos after the World Series of Poker began, in 1970.