If you hold Lundenvic, or you take it after talking to the old Roman at the Hadrian Wall ruins, you get Virio's Falcata, which has a swing of 50c and thrust of 15p. I got a Dux Helm Gold too, not certain from where - not a weapon really, more a protection from anything too legendary.
BTW: what are the instructions for the Quest: 'Find the Horn of Taliesion and the Horn of Arthur?' I click through the instructions assuming I could check them again in the notes. All I know is that I have to talk to a bard in one of the Pictish towns afterwards.