Nicolaus Mulerius (1564-1630): Dissimulating Copernicanism in the Revolting Dutch Republic

Abstract

Nicolaus Mulerius (1564-1630) was nominated in 1614 at the newly created University of Groningen as professor of Mathematics and Medical Science. His favorite topic concerned “mathematics” which, in practice, implied astronomy. In due course he published a textbook of astronomy (1616) and a new edition of Copernicus’ epochal De revolutionibus, the third since 1543 and the first annotated version (1617). Defending Copernicus at the new University -that is: at a University meant to produce ministers for the Reformed Church and therefore bound to the word if not the letter of the Bible- required quite some diplomatic skills. So Mulerius took care to have his new edition of Copernicus prefaced by the founder of the University, Ubbo Emmius, a beacon of Calvinist orthodoxy, while inventing various ways to subtly manifest his predilection without being “unmasked”. This attitude may be called “honorable dissimulation”. There was indeed all reason to be careful since -well-paying- theology students, not only Dutch Calvinists but also Lutherans from the German lands, constituted the core of the University’s population. As a matter of fact, in sticking to the letter of the Bible the Groningen theologians did not give way to their Roman-Catholic colleagues of the Curia in Rome. Mulerius’ “honorable dissimulation” is all the more remarkable. The discovery of a unique copy of the auction sale catalog of Mulerius’ private library (1646) made it possible, in this connection, to shed a more revealing light on his astronomical stance.