https://divinity.uchicago.edu/sites/default/files/imce/pdfs/webforum/052013/Gillespie%20Web%20Forum%20Final%201.pdf
"I will argue that Michael Servetus was the unacknowledged father or at
least forefather of liberalism."
"Non-Trinitarianism, however, did not always occupy a detestable position within Christianity. Indeed, before the Council of Nicaea in 325 AD it is likely that most Christians, at least in the West, were not Trinitarians but Arians who thought of Jesus as creature and not one with the creator. However, following Nicaea, Trinitarianism was gradually accepted as orthodoxy. A diverse Christendom in this way was replaced by a uniform Christianity. While Trinitarianism was dogma within the Western Chruch for almost a thousand years, it was never easy to make sense of it, although scolastic realism, which sought to combine Augustine's thought with a neo-Platonic reading of Aristotle, made a strong effort to do so. This effort, however, was rendered deeply problematic by the rise of nominalism, which denied the real existence of universals in favor of ontological individualism, a move that inevitably undercut the idea of the Trinity." (p.4)
"Filled with youthful zeal, Serverus denounced Christian doctrine in unequivocal terms in his On the Errors of the Trinity (1531) and other works."
"Servetus saw Jesus not as God but as God's highest creation and messenger on earth, a moral exemplar for all men. He rejected notions of original sin and predestination, proclaming that God does no condemn anyone who has not condemned himself through thought, word, or deed. Each individual in his view is given the same free will as Adam and Eve."
"The trial and death of Micheal Servetus did not put an end to anti-Trinitarianism, and in fact, helped to promote it."
"While religious toleration in Transylvania was due in part to political and sociological factors, the impact of anti-Trinitarian thought provided the foundation that made this liberal policy possible. The ideas of Servetus were first brought to Hungary and Transylvania by Jacobus Palaelogus, who hoped to use them to establish the ground for a universal religion that would allow for the peaceful co-existence of all monotheists."
"Also a new generation of undogmatic and more rationalistic Unitarians such as Samuel Crell offered a less thretening version of Unitarian though that helped pave the way for more enlightened views, that deeply influenced thinkers like Hobbes. Creel was in contact with Locke and Newton (and many other early Enlightenment figures as well), and the influence of Socinianism on their thought is incontestable.
Later Enlightenment thinkers also were influenced by anti-Trinitarianism. Bayle and Leibniz, for example, were deeply interested in anti-Trinitarian thought. Voltaire made Servetus the centerpice of his argument for religious toleration."
"Servetus and the anti-Trinitarians sought a path between that of the humanists and that of the reformers. Building on Erasmian humanism they imagined that human being were neither godlike beings nor irredeemable sinners. [...]
CEntral to this effort was their attack of the Trinity. If the Son and the Holy Spirit were actually one and co-eternal with the Godhead, humans must either rise to titanic heights to equal them or recognize their utter insignificance and beg for their forgiveness and mercy. If, however, Jesus was not a co-eternal moment of the godhead but a human being who was the voice of God and bore his message to man, then it would be possible for human beings to lead a life that was neither titanic nor depraved, to choose a life that was morally good by emulating the life of Jesus and following his simple commandments. Christianity in this sense could be a religion not of fanatical faith but of reason."
"I will argue that Michael Servetus was the unacknowledged father or at
least forefather of liberalism."
"Non-Trinitarianism, however, did not always occupy a detestable position within Christianity. Indeed, before the Council of Nicaea in 325 AD it is likely that most Christians, at least in the West, were not Trinitarians but Arians who thought of Jesus as creature and not one with the creator. However, following Nicaea, Trinitarianism was gradually accepted as orthodoxy. A diverse Christendom in this way was replaced by a uniform Christianity. While Trinitarianism was dogma within the Western Chruch for almost a thousand years, it was never easy to make sense of it, although scolastic realism, which sought to combine Augustine's thought with a neo-Platonic reading of Aristotle, made a strong effort to do so. This effort, however, was rendered deeply problematic by the rise of nominalism, which denied the real existence of universals in favor of ontological individualism, a move that inevitably undercut the idea of the Trinity." (p.4)
"Filled with youthful zeal, Serverus denounced Christian doctrine in unequivocal terms in his On the Errors of the Trinity (1531) and other works."
"Servetus saw Jesus not as God but as God's highest creation and messenger on earth, a moral exemplar for all men. He rejected notions of original sin and predestination, proclaming that God does no condemn anyone who has not condemned himself through thought, word, or deed. Each individual in his view is given the same free will as Adam and Eve."
"The trial and death of Micheal Servetus did not put an end to anti-Trinitarianism, and in fact, helped to promote it."
"While religious toleration in Transylvania was due in part to political and sociological factors, the impact of anti-Trinitarian thought provided the foundation that made this liberal policy possible. The ideas of Servetus were first brought to Hungary and Transylvania by Jacobus Palaelogus, who hoped to use them to establish the ground for a universal religion that would allow for the peaceful co-existence of all monotheists."
"Also a new generation of undogmatic and more rationalistic Unitarians such as Samuel Crell offered a less thretening version of Unitarian though that helped pave the way for more enlightened views, that deeply influenced thinkers like Hobbes. Creel was in contact with Locke and Newton (and many other early Enlightenment figures as well), and the influence of Socinianism on their thought is incontestable.
Later Enlightenment thinkers also were influenced by anti-Trinitarianism. Bayle and Leibniz, for example, were deeply interested in anti-Trinitarian thought. Voltaire made Servetus the centerpice of his argument for religious toleration."
"Servetus and the anti-Trinitarians sought a path between that of the humanists and that of the reformers. Building on Erasmian humanism they imagined that human being were neither godlike beings nor irredeemable sinners. [...]
CEntral to this effort was their attack of the Trinity. If the Son and the Holy Spirit were actually one and co-eternal with the Godhead, humans must either rise to titanic heights to equal them or recognize their utter insignificance and beg for their forgiveness and mercy. If, however, Jesus was not a co-eternal moment of the godhead but a human being who was the voice of God and bore his message to man, then it would be possible for human beings to lead a life that was neither titanic nor depraved, to choose a life that was morally good by emulating the life of Jesus and following his simple commandments. Christianity in this sense could be a religion not of fanatical faith but of reason."