When Dumbledore first left Harry in the care of Petunia and Vernon, he invoked powerful protection charms to prevent the Death Eaters from finding Harry's location. At this point, it is assumed that Sirius Black is a Death Eaters. If that is the case, how was Sirius able to find Harry's house when it was supposed to have been protected? As Lily's friend, Sirius might have known the address, but the protection should've been stronger if it was known that Harry's location would be discovered - right?
I recall Dumbledore telling Harry that as long as he was with his kin, he was protected by love - until he would come of age at 17. I do not remember anywhere in canon that said Number 4, Privet Drive was under Fidelius.
It also could not have been protected because Ron had found the house with Fred and George in the beginning of CoS. Harry didn't ever tell Ron or Hermione his home address; he usually referred to it as Privet Drive, as Ron refers to his home as The Burrow, which is not the actual address.
Correct, it wasn't. It was only protecting Harry from a direct attack by Voldemort while he could call the place home, at least at that place specifically.– PryftanFeb 13, 2018 at 23:59
I'm not aware of any answer from canon (books or interviews) but Sirius was one of the Marauders. He'd have known Lily extremely well (being James best friend and Harry's Godfather) and would have likely known that Lily's sister got married and to whom.
Also, I don't recall that Dumbledore actually hid Harry's location - the house wasn't under Fidelius.
But that was common knowledge - so what prevented the Death Eaters and other people who wanted to see "The Boy Who Lived" from tracking him? Apr 24, 2014 at 17:37
@mustard - They could track him but couldn't harm him due to Dumbledore's protection based on Lily's sacrifice magic. On a separate note; I don't think it was "common knowledge" that one Muggle married another Muggle among Wizards - especially DEs). Apr 24, 2014 at 17:44
Don't forget that Sirius loaned Hagrid his motorcycle. It would not be unreasonable to assume that Sirius asked Hagrid where he was going.– TGnatApr 24, 2014 at 18:03
@DVK By common knowledge - I meant that the Death Eaters surely knew about Lily's ancestry and had the means to track her sister if necessary. Apr 24, 2014 at 23:04
1I doubt that Dumbledore's protections were somehow designed for "Death Eaters" only as that is a designation. The only magical aspect was the Death Mark. My guess is Dumbledore's protection was against those who wished to do harm to Harry. Sirius wasn't intending any harm to Harry so the protections wouldn't affect him. Apr 25, 2014 at 1:54
Keep in mind that Sirius was not really at Privet Drive 4. Harrys first encounter with him was after he left and was standing on the street. So even if the house was protected, it might just be that he waited until Harry left the house.
Couldn't it be as simple as, the charm was to protect him from Death Eaters, but as he wasn't one, the charm didn't affect Sirius?
It was Voldemort only and it wasn't said to be anything but that he couldn't harm Harry there rather than hiding the place.– PryftanFeb 13, 2018 at 23:58