Some of the symbols described in the 1965 science fiction novel Lord Kalvan of Otherwhen by H. Beam Piper:
Top, the emblem of the high god Dralm, traditional head of the Zarthani pantheon: A blue eight-pointed star on white.
Middle, the flag of the newly-established Great Kingdom of Hos-Hostigos: A red keystone on a dark green field.
Bottom, the flag of the principality of Hostigos (Old Hostigos): A blue halberd-head on a red field.

Other flags described in the book (but not included in the graphic) are the flag of the principality of Nostor (an orange lily on a black field) and the flag of the principality of Sask (a golden-rayed sun on a green field).  The colors of the principality of Beshta are black and pale yellow, but the flag is not specified.  Black and white are the "colors of unemployment" for mercenary soldiers.
Made from scratch by User:AnonMoos based on the purely verbal descriptions contained in the H. Beam Piper book, except that the halberd head was modified from image File:Héraldique meuble hallebarde.svg by User:Henrysalome
User:AnonMoos, except halberd modified from vector outline by User:Henrysalome