jan 1, 1250 - (sometime before 1250) Guilielmus Peraldus wrote "Summa Vitiorum"

Description:

- hugely influential treatise on how to understand sinfulness
- became a very useful source when there was a big push for the education of priest s after the Fourth Lateran Council decreed that ea penitent must confess to his priest once a year and the priests had to be educated in the workings of their own minds and sinfulness

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