Beginning around 1920, the ancient Chinese game Mahjong gained popularity in America and Europe. When Charles Babcock simplified the rules and published his "red book," those rules quickly became the standard. Parker Brothers purchased his rules and the copyright on his font and title "Mah-Jongg." But later, Parker allowed the copyright to expire, as Mah-Jongg became less popular, and players refined the rules even more. Groups of players, especially among the Jewish community, kept the game alive throughout the 20th century. It has enjoyed something of a revival in the early 21st century as younger players are drawn towards traditional games and to the beauty and complexity of Mahjong sets. A photograph from the early 1960s shows Philadelphian Charlotte Levy, second from left, and three friends enjoying a Mahjong game.