Which Jarvan did Sion Kill? Figuring out Sion's age.

Is there any confirmation? We can rule out J4 obviously and I think J3 is extremely unlikely due to the fact that it is J4's father and a big deal wasn't made of it by Riot. So either J1 or J2. Considering each Jarvan (except 4) had a child when they were around 30 years old, we can assume that it has been around 60-100 years since the death of Sion. Which is a really cool concept to me, he isn't some ancient mythical being, it's fact that he once lived and that he was a great war hero. It'd be like if we resurrected FDR or Abraham Lincoln to be president again, it's a huge deal.