What saved Harry?

[Maria Elmvang]

No: HPFGUIDX 142570

Hi all,
I have recently reread the series, and have come up with one thing that puzzled me. I have a feeling it's answered in one of the books, but cannot remember where nor the answer, so I'm hoping one of you will be able to help me. Forgive me if it's a stupid question.

Why was Voldemort unable to kill Harry? I know we were originally told that it was because his mother died to save him, but surely Lily wasn't the only mother who did that!! There must have been more to it. Especially when Voldemort not only wasn't able to kill Harry, but the curse reflected back on him and almost killed him instead. I'm sure I've read the answer to this *somewhere* but can't remember what it is, so I'm not even sure if I read it in canon or fanon. Can anybody help me out here?

Maria
 --
I believe in God like I believe in the sun
not because I see it, but by it
I see everything else
--- C.S. Lewis