Gotthold Lessing's 1779 play Nathan the Wise doesn't quite hold up as theatre, but it survives as a didactic argument for religious tolerance. Lessing's play is unique for its time in making the Jewish patriarch Nathan, modeled after Lessing's friend Moses Mendelssohn, the central character of the piece. The play further makes its case with the often-noted 'ring parable' in the third act, which suggests that religious tolerance between the three major monotheisms (Judaism, Christianity, and Islam) through a rational understanding of the limits of human knowledge.
According to the parable, an Eastern patriarch owned a ring with "the magic power that he who wore it, trusting its strength, was loved of God and men." The patriarch had three sons and, while on his deathbed, realized that all three would wish to inherit the ring. So, he had a jewler make two more rings, "in all points identical", and gave each son one of the rings, claiming that it was the magic ring. The sons eventually go to battle and then to court over the rings, still not knowing which is the true ring. The Judge's advice to the sons: "Accept the matter wholly as it stands, if each one from his father has the ring then let each one believe his ring to be the true one. Possibly the father wished to tolerate no longer in his house the tyranny of just one ring! Let each aspire to emulate his father’s unbeguiled, unprejudiced affection! Let each strive to match the rest in bringing to the fore the magic of the opal in his ring!"
The parable offers a solution to the domestic religious tensions in the play, but it also suggests an answer to religious strife based on an honest empirical assessment of the limits of our own knowledge. Lessing argues that our limited knowledge should prevent any of us from deciding that we are of the 'one true faith', or that other monotheistic religions, having the same source, are 'false religions'. However, by seeming to limit what it is that we can say for sure about religion to the fact that it is given by God, and that we cannot know His will, but should live virtuously, the play seems to argue for Deism. Certainly, the fact that Lessing was a Mason is not incompatible with a belief in Diesm.