Septimus III was a planet in the Cardassian Union. In 2375, the Klingons invaded the planet and slaughtered the Eleventh Order, over 500,000 Cardassians; the Dominion had tasked a grand total of three Galor-class vessels to defend the planet against fifteen divisions of Klingons. (DS9: "Strange Bedfellows", Star Trek: Sigils and Unions--The Thirteenth Order)