McGonagall: More Important Than Turning Into a Cat?
An original editorial by Alvin Simpson
One of the spells and enchantments protecting Hogwarts besides walls that Hermione is always telling everyone may well be a Fidelius Charm. There are a lot of people who could be the secret keeper, but one person who stood out the most was Professor Minerva McGonagall.
Dumbledore trusts McGonagall a lot or he wouldnt give her such important tasks. She also has a lot of duties that make her important enough. The main thing that sticks out that could make her Secret Keeper that a lot of people over look is the first time a student hears from Hogwarts. I am talking about, of course, when they get their letter from Hogwarts. Its McGonagall that sends it telling you youve been accepted to the school and telling you where to be at what time to get to there.
McGonagall has been teaching at Hogwarts for a long time, forty years before OotP, so even if they had started using the Fidelius Charm when she started just teaching it would have been a short enough time ago that Voldemort wouldnt have been at school. Most likely she didnt just waltz into Hogwarts on her first day and be appointed Deputy Headmistress. So here is how I see it: Voldemort starts unleashing terror throughout the Wizarding world, so to keep the students safe Dumbledore puts the Fidelius Charm on Hogwarts. McGonagall, being Deputy Headmistress has the task of sending the letters to all the students that will be coming to Hogwarts, is made Secret-Keeper so when she sends the letters to the students they can see the school and know where its at. Also, after Voldemort left school is when he spent all those years going through the transformations he did, when McGonagall probably got the Deputy Headmistress position.
Sirius, James, Peter, and Remus all were at school when Dumbledore was headmaster, and he was a Transfiguration teacher beforehand, which Im guessing thats who McGonagall filled in for, so they (Sirius, James, Peter, and Remus) got the letter from McGonagall when they arrived and knew where the school was. That is how Sirius got into the castle. Also, Lucius Malfoy was 41 (OotP ), so he also would have gotten the letter to Hogwarts, or he got it by being a school governor until the end of CoS, so he could have gotten in with a letter either way.
When thinking this over one thing came to me that can question this however. How did Voldemort get inside Hogwarts during Harrys first year then? The answer is pretty simple actually. Voldemort was living off of Quirrel who worked at the school so he knew where it was, and since they were basically one being, except the face growing off the back of Quirrels head, he could have gotten inside the school.
This could be possible, then again it could not. Also it could be that Hagrid could be Secret-Keeper and evidence can be found in an excellent editorial here. I find that McGonagall is an excellent person to be it because there is proof that she has contact with every single student entering Hogwarts from when Dumbledore became Headmaster and on. This will be something we will find out in the future books to come.