Censorship makes new ideas less available to others, but also reduces the number of
people choosing to develop non-compliant ideas. We propose a new method to measure
the eect of censorship on knowledge growth, accounting for the agents' choice between
compliant and non-compliant occupations. We apply our method to the Catholic Church's
censorship of books written by members of Italian universities and academies over the pe-
riod 1400-1750. We highlight new facts: once censorship was introduced, censored authors
were of better quality than the non-censored authors, but this gap shrank over time, and
the intensity of censorship decreased over time. We use these facts to identify the deep pa-
rameters of a novel endogenous growth model that links censorship to knowledge diusion
and occupational choice. We conclude that censorship reduced by 35% the average log
publication per scholar in Italy, while adverse macroeconomic processes are responsible
for another 9% reduction. The induced reallocation of talents towards compliant activities
explains half the eect of censorship.