Earlier time frame before HP was born (also Pottermore)

[Geoff]

No: HPFGUIDX 191319

--- In HPforGrownups at yahoogroups.com, "catmcnulty" <CatMcNulty at ...> wrote:

Cat:
>  One of the things that I be interested to find out is How many and Who were the DADA teachers between the time Riddle/Voldemort was refused the position and Quirrell? 

Geoff:
It would seem only part of this question can be answered. I do not 
believe that there is a definitive list of the DADA teachers through 
this period.

He was refused the post by Armando Dippett when he was eighteen. 
When Myrtle was killed and the Chamber of Secrets opened, this was 
in 1942 when Riddle would be somewhere between 16 and 18, 
putting his request at, say, 1944. He had been told to reapply in a 
few years.

In the Pensieve record of Riddle's meeting with Dumbledore, he said: 
"I have returned later perhaps than Professor Dippett expected."
(HBP "Lord Voldemort's Request" p.414 UK edition)

Perhaps 5 years? Making this about 1949. Quirrell took up the post 
in 1991. Hence, the answer to how many teachers would seem to 
be something around 40.

Cat:
And how many years did Quirrell teach DADA ... because he had just recently returned from a sabbatical in Albania when he met Harry for the first time.

Geoff:
Only one. Two pieces of evidence. 

Dumbledore, talking to Harry after the scene I have just mentioned, says:
"Oh, he definitely  wanted the Defence Against the Dark Arts job. The 
aftermath of our little meeting proved that. You see, we have never 
been able to keep a Defence Against the Dark Arts teacher for longer 
than a year since I refused the post to Lord Voldemort."
(ibid. p.418)

Hagrid mentions the year of absence  when they first meet:
"Is he always that nervous?"
"Oh, yeah. Poor bloke. Brilliant mind. He was fine while studyin'  outta 
books but then he took a year off ter get some first-hand experience."
(PS "Diagon Alley" p.55 UK edition)

In a Bloomsbury online Chat on 20/07/2007, Jo Rowling was asked about
Quirrell's time at Hogwarts and her answer was:

" He was teaching at Hogwarts for more than a year, but NOT in the post 
of DADA teacher. He was previously Muggle Studies professor.'