During their time in Poland, the Polish Brethren were recognised as one of the most influential intellectuals in the commonwealth, relevant not only in the country, but also abroad. It is estimated that around the year 1620, at the highest point of Polish Arianism, not even 1% of the general population belonged to the Polish Brethren. Artists and intellectuals are a different story – around 20% of them were a part of this movement. Names such as Andrzej Frycz Modrzewski, Zbigniew Morsztyn and Wacław Potocki immediately come to mind. The church was also in charge of the Racovian Academy, a university known throughout Europe as ‘the Sarmatian Athens’.
Abroad, a really astounding number of intellectuals, especially from Great Britain, read and engaged with the movement. Among the most recognisable, it is impossible not to mention John Milton, who, during his trial in the Rump Parliament in 1652, was accused of being a member of the religion by Oliver Cromwell. Later on, the writings of Polish Unitarians such as Samuel Przypkowski could be found in the libraries of John Locke and Isaac Newton. Thus, it can be said that the Brethren’s theories were one of the foundation stones for the upcoming Enlightenment, influencing, directly or indirectly, the likes of Spinoza, Kant and the American Founding Fathers, as well as Stanisław August Poniatowski and other authors of the first Polish constitution.