"But, you know, the life that we had, I mean, that was amazing, too, and it wasn’t a spell or a prophecy. It was real. We fell in love on our own. We had ups and downs, we fought. We changed, both of us. We grew, and we grew apart, but that is real. I mean, that’s life."
You all know, of course, that Hogwarts was founded over a thousand years ago - the precise date is uncertain - by the four greatest witches and wizards of the age. They built this castle together, far from prying Muggle eyes, for it was an age when magic was feared by common people, and witches and wizards suffered much persecution.