If this helps at all, a little timeline (I've not read Vanguard yet so taking the Vrax info as described by others):
- 2265:Vrax is Praetor per Vanguard
- unseen: Vrax is killed by his son "Smirky" who takes the Praetorship
- late-2265/early-2266: Edginton Alien Spotlight, featuring tests of "ghost ships" in Romulan space
- 2266: Byrne's Alien Spotlight, ghost ship development appears to be complete, leading straight into Balance of Terror
- Balance of Terror
- 2266-2268: The Hollow Crown. Starting shortly after Balance of Terror, then skipping ahead to The Deadly Years, then skipping ahead several more months. In this time the Klingons manipulate the Romulan Commander's family and the Praetor so that the Commander's son ends up inheriting the praetorship (with a built in hatred for the Federation so the Klingons can use the Romulans as a weapon and get round the Organian Peace Treaty)
- Schism will continue on from there showing the end of the alliance.