According to the Wikipedia article on the Knights of Pythias, it is a fraternal organization and secret society founded at Washington, DC, on 19 February 1864. The Knights of Pythias was the first fraternal organization to receive a charter under an act of the United States Congress. It was founded by Justus H. Rathbone, who had been inspired by a play by the Irish poet John Banim about the legend of Damon and Pythias. This legend illustrates the ideals of loyalty, honor and friendship that are the center of the order. The order has over two thousand lodges in the United States and around the world, with a total membership of over 50,000 in 2003. Some lodges meet in structures referred to as Pythian Castles.

The order's auxiliaries are the Pythian Sisters, the less serious Dramatic Order Knights of Khorassan, The Nomads of Avrudaka, and two youth organizations: the Pythian Sunshine Girls and the Junior Order, Knights of Pythias for boys.

A member must be at least 18 years of age. He cannot be a professional gambler, or involved with illegal drugs or alcohol and he must have a belief in a Supreme Being.