This planet was the headquarters of the Cardassian Twelfth Order and one of the most heavily fortified positions in the Cardassian Union during the Dominion War. At that time, a direct assault by fifteen Vor'cha-class attack cruisers was considered barely able to scratch the planetary defenses.
In 2375, Chancellor Gowron suggested that it should be the Klingons' next target despite the objections of General Martok and Commander Worf. Ultimately, Sarpedion was not attacked, as Gowron was killed by Worf in ritual combat shortly thereafter. (DS9: "Tacking Into the Wind")