General History/Crazy Monarchs
I heard that there have been monarchs who were on the verge of insanity, which could be attributed to their fatherís senseless struggle to produce a male heir and consequently fathering the child at a very late age. And because there is evidence to support the idea that having an older father predisposes one to mental illness, the insanity of these monarchs could in fact be due to their fatherís lifetime struggle.
A shred of truth?
The late age of some of the kings when they sired some of their children could have an impact on the sanity of the offspring. There is an increased risk for having a child affected by schizophrenia at some time in their life if the father is over 50 years of age. Studies have shown a direct correlation between the number of mutations or slight alterations to the DNA, of the child and the age of their father. Obviously this is not the only reason for insanity in rulers. Genetics, environment and upbringing play a parts as well.