Corday initially planned to assassinate Marat in front of the entire National Convention. She intended to make an example of him, but upon arriving in Paris she discovered that Marat no longer attended meetings because his health was deteriorating due to a skin disorder (perhaps dermatitis herpetiformis). She was then forced to change her plan. She went to Marat's home before noon on 13 July, claiming to have knowledge of a planned Girondist uprising in Caen; she was turned away by Catherine Evrard, the sister of Marat's fiancée Simonne.