But there's no hint that the Romulans ever held
Khitomer, just that they attacked
it. We have no astropolitical context for the attack, either. Were the Romulans striking back at Klingons for a previous assault? Were the Romulans that hit Khitomer even acting under the orders of the Senate? Could they have been Romulan privateers or perhaps renegades?
Given that Narendra and Khitomer were struck within two years of each other suggests that there was
a state of war between the Klingons and the Romulans, but how invested each side was in the war is unclear. There may not have been any exchange of territories at all during this war, just hit-and-run attacks on planets and some ship-to-ship battles.