The book I read described him as a hub in the intellectual internet of his time.
https://en.wikipedia.org/wiki/Marin_Mersenne :
Marin Mersenne (also known as Marinus Mersennus or le Père Mersenne; French: [mɛʀsɛn]; 8 September 1588 – 1 September 1648) was a French polymath, whose works touched a wide variety of fields. He is perhaps best known today among mathematicians for Mersenne prime numbers, those which can be written in the form Mn = 2n − 1 for some integer n. He also developed Mersenne's laws, which describe the harmonics of a vibrating string (such as may be found on guitars and pianos), and his seminal work on music theory, Harmonie universelle, for which he is referred to as the "father of acoustics". Mersenne, an ordained Catholic priest, had many contacts in the scientific world and has been called "the center of the world of science and mathematics during the first half of the 1600s" and, because of his ability to make connections between people and ideas, "the post-box of Europe". He was also a member of the Minim religious order and wrote and lectured on theology and philosophy.
A deeply religious Catholic -- though notably in France not in the Spain of the Inquisition.
