The artist Michelangelo may have had the condition Asperger's Syndrome, according to researchers.
The Sistine Chapel is Michelangelo's most famous work
Two experts in Asperger's, a milder form of autism, say the artist had many of the traits linked with the condition which causes social problems.
"Michelangelo was aloof and a loner," said psychiatrist Dr Muhammad Arshad, one of those involved in the research.
He added that Michelangelo's father and grandfather, as well as one of his brothers, had autistic tendencies.
The research, by Dr Arshad and Professor Michael Fitzgerald of Trinity College Dublin, was published in the Journal Of Medical Biography.
The pair describe Michelangelo, who died in 1564, as "strange, without affect, and isolated," adding that he was "preoccupied with his own private reality".
"His single-minded work routine, unusual lifestyle, limited interests, poor social and communication skills and various issues of life control appear to be features of high-functioning autism or Asperger's Syndrome."
They also compared his personality to that of Regency architect John Nash, who also lived with the condition.
People who with Asperger's Syndrome often display talents in a particular area, such as maths or art.
According to the National Autistic Society, Dr Fitzgerald first suggested that Michelangelo may have had the condition in a book published four years ago.
He has also published theories on whether several prominent mathematicians, scientists and authors may have also had Asperger's.
"The evidence would be drawn from autobiographical accounts or other people's contemporary descriptions of their behaviour," said a spokeswoman for the society.
"However, any conclusions drawn about them at this historical remove would be speculative."