In the summer of 1793, Jean-Paul Marat was assassinated by Charlotte Corday of Caen. Corday's allegiances were Girondin and she blamed Marat for the atrocities of the September Massacre the year before, an event which he was a major proponent for. She arrived to Marat's flat under the guise of having news of Girondin activity in Normandy, and Jean-Paul's wife let her into his medicinal bathing chambers, for Marat suffered from a rare skin disease. Corday ditched her facade after he confirmed his violent intention for the Girondins, driving a dagger into his chest. Corday was then caught, tried and guillotined, with no resistance on her part.

The death of Marat would rally Montagnard (Jacobin) forces against the Girondins, eventually leading to the Jacobins' Reign of Terror, perpetuated by ther rally cries of Jacques-Louis David's artwork of the scene. Both Corday and Marat were portrayed as martyrs for their actions to their respective factions, immortalizing the events in the wake of the escalation of conflict deeply embedded in France during the revolution.

References:

http://francerevisited.com/2012/07/charlotte-corday-and-the-bathtub-assassination-of-jean-paul-marat/

https://www.history.com/this-day-in-history/charlotte-corday-assassinates-marat