To take the diary or not

Riddle offering the (stolen) diary to Harry

Roger Bacon's diary is a diary given by Professor Quirrell to Harry Potter in October 1991. According to Quirrell, the diary belonged to 13th-century muggle philosopher Roger BaconW. This is a significant gift to Harry as Roger Bacon can be considered one of the earliest advocates of the scientific methodW.[1][2]

According to Quirrell, Roger Bacon was a muggleborn wizard who got accepted to Hogwarts but refused to go and instead investigated magic by himself, recording his research into the diary.

In June 1992, Voldemort uses the diary to make a horcrux (canon) for Hermione Granger.

Canon counterpartEdit

See T. M. Riddle's Diary.


  1. Author's notes for Ch. 27
  2. Not to be confused with 15/16th-century muggle philosopher Francis BaconW who is one of the fathers of the scientific method and who Harry mentions in Ch. 7.