Tulvan is a retired textiles and fur trader who worked out of Bruma for years but came back home to windhelm for retirement. He's a generally jovial man but can be rather stern and fearsome when crossed; almost like a night and day demeanor. He takes in the sights at the museum on a regular basis as he's always been fairly well read, it being his main hobby between work obligations and now he can spend most of his retired years learning even more.  

For reference think of "Sir Hector" from the Disney animated sword in the stone movie. I imagine a similar but jovial tone.