He left IHÉS around 1970 but he stayed active in math, and he kept working as a math professor and later at the CNRS (French research institute). https://en.wi

He left IHÉS around 1970 but he stayed active in math, and he kept working as a math professor and later at the CNRS (French research institute). https://en.wikipedia.org/wiki/Alexander_Grothendieck#Manuscripts_written_in_the_1980s https://en.wikipedia.org/wiki/Alexander_Grothendieck#Manuscr...