As an exercise in the power of the law of unintended consequences, the reign of Augustus the Strong Elector of Saxony and later King of Poland is amongst the best. Augustus reigned as Elector in Saxony from 1694-1733, he was fortunate enough to be elected as King of Poland three years into his reign in 1697. As King he commanded the entire resources of the Commonwealth of Poland and Lithuania- at that point one of the great powers of Europe (and beggining its great decline until its demise as a state in 1795). To become King of Poland though, Augustus had to renounce his Lutheranism. Like Henri of Navarre, Augustus found that Warsaw was worth a mass and became a Catholic but the consequences of this religious change in Saxony were vast and important for the future history of Germany.
As Jonathan Israel tells it (Radical Enlightenment p.106-7), Augustus's decision to become a Catholic meant that the court in Dresden refused to accept Lutheran censorship of books and manuscripts within the electorate. As Leipzig, within Augustus's domain, was by 1700 the largest book trading city in Germany (to compare in 1700 Leipzig had eighteen publishing houses and booksellers and a whole community of binders and other crafts, Berlin reputedly had one bookshop and Koenigsburg, a university town, but three)- the knock on effect was to change the way that the German book market itself operated. Moving censorship from the religious to the secular arm did not cease censorship: the works of Spinoza, Radicati and others were still proscribed, but what it did was to cease confessional censorship. So long as Calvinists, Lutherans, Catholics and even moderate enlightened Christians were willing to refrain from attacking each other, they might be published in Saxony. The outcome of course, allied with developments in other Kingdoms such as Prussia under Frederick the Great was to change German publishing and therefore German intellectual life. Augustus the Strong's conversion had an important impact therefore on the enlightenment during the early eighteenth century: Warsaw may have been worth a mass, it was also worth a library.
This prompts two reflections: which I think are also substantiated by Israel's work. The first is that the early enlightenment proceeded along physical channels of book selling, manuscript smuggling and letters. Without those physical channels and the markets in Western and Eastern Europe that were willing to accept the books and manuscripts and devour them, there would and could have been no enlightenment as we understand it. The second was that that was all facilitated by a movement of censorship across the continent from the religious to the secular arm: and by disputes and politics which had nothing to do with the enlightenment within the secular arm. Augustus's Polish crown is one example, the fortunes of Neapolitian intellectuals in Austrian and Spanish Naples is another, we could add others to the list but I think that is enough to prove that broader point. Intellectual life was at the mercy of politics and that meant that there was no consistent response from the ancien regime to the enlightenment. Israel's work illustrates both the ways the enlightenment was transmitted and the complicated ways that the censorship of that transmission operated.