Does anyone know what Knights of Pythias are??

Wtf is this one?

The Knights of Pythias is a fraternal organization and secret society [2] founded at Washington, DC, on 19 February 1864.
Knights of Pythias in a parade in Racine, Wisconsin, ca. 1910

The Knights of Pythias was the first fraternal organization to receive a charter under an act of the United States Congress.[3] 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.