ShiVang's flagship

From Memory Alpha, the free Star Trek reference.

ShiVang's flagship was a Klingon starship in service in the mid-24th century, commanded by General ShiVang.

Martok served on the flagship for five years as a civilian laborer. Some time later, the ship was boarded by the Romulans and Martok helped to fight them off, earning himself a battlefield commission for doing so. (DS9: "Once More Unto the Breach")

Martok's quote that he has hated Kor's "name for almost thirty years" would put his service on the flagship and the Romulan attack sometime in the late 2340s/early 2350s.