Calvin and Servetus

A recent letter asks:

Do you know if Calvin really wanted Servetus put to death? I know he wrote he wouldn't stop it, if he were put to death (paraphrased). I know the two often corresponded, until Calvin lost patience. But a Reformed guy told me, last summer, that when Servetus wrote he wanted to come to Geneva or Vienna, I forget which, Calvin tried to discourage him? And that when he did get arrested, and sentenced to burn alive at the stake, Calvin tried to get the sentence mitigated to the quicker and more humane decapitation?

A few months back Dr. White provided a very helpful overview on this issue on the Dividing Line. I extracted the 20 minute section on Calvin and Servetus.