(I'll assume the following party split for information-gathering: Fendric & Hiritus, Nurthk & Shavah, Raven & Tatlock, Oliver & Xiao... For each group, I'll base results on the higher of the two checks, with a +2 bonus if the other check is above 10. If you'd prefer different groupings, feel free to state so.)
Nurthk & Shavah: For the most part, the commonfolk don't seem too sure about the history of Thedoric, but with a few drinks, Nurthk is able to get some to share what they do know. Lord Thedoric's name is known mostly as simply the name on the monument; the "Tournean incursion," it seems, happened roughly thirty years ago. It didn't concern the common population much, save for rumors of and early preparations for a war with Tourne. The war never materialized, and Thedoric was apparently credited for this. (Note: Mark off 10 gp.)
Shavah, for her part, can't get anyone to say much of anything on the subject. Dejected, she sits, drinks, and lets Nurthk do the talking. (Fumble.)
Raven & Tatlock: Initial results are discouraging, as much of the population appears ignorant of this bit of history, but Tatlock strikes gold with an older half-orc who seems impressed by what he must perceive as the boy's youthful curiosity.
"This all happened when I was a much younger man, working as a clerk in the Defense Armory, but I'll share what I can remember," he begins. "It started with rumors, first, and then a notice came to prepare for the possibility of battle -- that meant double-checking all the gear for defects and needed repairs, confirming the supply charts against the available Defensemen, and so forth. Tourne had starting building military ports along the North shore, understand, which was taken by the boots in charge as a fairly threatening action. Anyway, before we even had a complete soldier's sort ready word came down to resume normal peacetime activity, which meant of course we had to go back and sort everything back into by item, that's instead of by man. Short of it was, it was a big fuss about nothing: Tourne just sort of packed up and went back to Tourne. Far as I could tell, it was just a lot of foot-stamping, no real 'cause for concern. I do recall they had some ceremony for erecting that monument, but I didn't attend. Seemed over and done with already, as far as I was concerned." (However much more he knows or is willing to share will, of course, be dependent on Raven's check.)