Who took Sir Simon to the "Garden of Death"?

Virginia Otis takes the ghost of Sir Simon to the "Garden of Death."  
In part five of the story, Virginia Otis is speaking with Sir Simon.  He explains to her that he is so very tired and wants to sleep.  Virginia, in her innocence, explains that sleeping easy.  

"That's quite absurd! You have merely to go to bed and blow out the candle. It is very difficult sometimes to keep awake, especially at church, but there is no difficulty at all about sleeping. Why, even babies know how to do that, and they are not very clever."

Sir Simon explains that he hasn't slept for three hundred years, and Virginia asks him where he could go to find sleep.  Sir Simon tells her about a garden where he can find sleep.  The garden is the "Garden of Death."  Sir Simon explains that in order for him to get there and find eternal rest, he needs Virginia's help.  She must pray for him and weep for his sins.  Sir Simon will be granted access because a pure girl is escorting Sir Simon.  Virginia agrees to do this for Sir Simon, and together they enter another ghostly dimension of sorts where the "Garden of Death" can be found.