Was Frederick II of Hohenstaufen really a medieval Dr. Mengele?

Question

According to legend, the Holy Roman Emperor Frederick II, who was intelligent (spoke six languages) and influential, also purportedly used cold-blooded methods to further his "scientific" inquiries. According to the Wikipedia entry:

[Frederick] was also alleged to have carried out a number of experiments on people. These experiments were recorded by the monk Salimbene di Adam (who despised Frederick) in his Chronicles. Amongst the experiments included shutting a prisoner up in a cask to see if the soul could be observed escaping though a hole in the cask when the prisoner died; feeding two prisoners, sending one out to hunt and the other to bed and then have them disemboweled to see which had digested their meal better; imprisoning children without any contact to see if they would develop a natural language.

I've read this elsewhere long ago, and as there isn't too much information about Frederick, I'm wondering if anyone can point to a definitive source. Certainly Salimbene di Adam might have had an axe to grind, but the consistency of the accounts makes them seem believable and, given the character of Frederick (his belief in reason, his winning of Jerusalem by treaty rather than by war), which points to an unconventional mind that was unhobbled by conventional restraints.

Can anyone clarify this issue? Was Frederick a real monster or someone who had been given the 13th century version of a swift-boating by the Church he defied?

Answer 1

I found a number of various sources that had different versions of the examples you provided from Wikipedia. For example, one story claimed that he put a number of prisoners in an airtight room and then once he was certain they had suffocated, he had the door opened very slowly so that he could observe whether or not their souls could be seen escaping the room. With the experiment on infant children, each example I found stated that the mothers were instructed to not speak or show any form of expression towards the children so that he could see if they would develop natural speech on their own. There were different views on whether the experiment involved two, three, or possibly more children, but all sources agreed that each of the children died before developing any speech patterns.

Perhaps the best answer to this came from a Lecture in Medieval History:

Not all of his scientific bent was exercised [in] such unacceptionable ways; he often engaged in bizarre physical experiments. With Frederick one never knows whether what one reads in sources from the period is an honest attempt to tell the truth about him, a fantastic bit of gossip, or a downright lie.