We re-examine Mersenne's critique of Giordano Bruno concerning the question of the extension of the universe and the plurality of worlds as well as that of universal animation. For this, it is necessary to distinguish, especially in the examination of the first question, the strictly cosmological problem from its metaphysical and theological foundation in which the relation between God and the universe is resolved. Mersenne's critique fundamentally concerns this second side of our problem, according to his conviction that Bruno repeats the age-old errors of philosophical paganism and reaffirms an ‘impiety’ completely incompatible with Christian doctrine.