During the 1870-1914 period, school principals – distinguished from other teachers by this promotion – were central in the field of primary public schooling in the Seine department (in and around Paris). We use a statistical study of careers and a qualitative analysis of administrative correspondence to reconstruct the web of social ties that, in the context of a deeply changing institution (with many new schools and a drastic secularization policy), allowed some individuals to be chosen to govern the largest schools. Our choice of mixed methods (taking into account the discourses of various actors as well as using multivariate event history analysis models) allows us to disentangle a complex social world.