"Defense Against the Dark Arts ... was being taught at the time by an old Professor by the name of Galatea Merrythought, who had been at Hogwarts for nearly fifty years."
-- Albus Dumbledore, discussing events of 1945 (HBP20)
Galatea Merrythought starts teaching at Hogwarts
Date circa 1895
Location in Canon HBP20
Type of Event Wizarding world