If the Founders weren’t so careful and well known in the world, they wouldn’t have put those anti-scrying enchantments on their relics. Rather annoying, that would have made things a lot easier. Besides Voldemort, I was the only person who had seen all of them at once. Even held them in my hands at one point. A very important, and restrictive, requirement when it came to scrying. It also doesn’t work on living matter, so scrying Voldemort to see what he was doing was not possible. My promise was the only thing that could direct me towards it, but Hogwarts has been hiding it rather well.