Josef Fritzl, the notorious Austrian incest father, today claimed that he had been abused as a child.
As the trial against him opened in St Pölten, west of Vienna, the 73-year-old retired electrical engineer admitted rape, incest and false imprisonment, but denied enslaving daughter Elisabeth.
Nor did he murder one of the children born to Elisabeth in captivity, he maintained.
"I had a very difficult childhood," Mr Fritzl said in a trembling voice. He told the three judges and eight jurors that, at the age of 12, he had made it clear to his own mother that he would not tolerate being beaten any longer and would defend himself.
"From that point on, I was Satan personified for her," he said. She never showed him any affection and his father appeared only "rarely and sporadically", he said.
His relationship with his mother was never close, even though they shared the same house until her death in 1980.
Mr Fritzl attributed his mother's coldness to her own childhood. "Her life wasn't the best, either," he said. "She grew up on a farm and had to work from the age of eight."
Opening the trial, state prosecutor Christiane Burkheiser gave a chilling account of the cellar life.
She said Fritzl did not talk to his daughter during her first few years in the soundproof basement. She used a laser pen to outline how low the cellar's ceiling was, about five feet, and to detail the dimensions of the last door leading into it, which could only be accessed by crawling through on the hands and knees.
"I have been to the cellar twice," she told jurors as Fritzl stared ahead at Judge Andrea Humer, his back to the press and public.
"It smells, it is incredibly damp. It has a morbid atmosphere that hits you as you crawl through the 83 square centimetre entrance hole.
"The damp creeps in within minutes. There is wet rot. And he was the absolute ruler of this kingdom. He had complete control."
Mrs Burkheiser said: "She had no washbasin, no bath, no shower, often no heat. He would come, switch the lights off, rape her, leave. Lights off. Rape. Lights on. Mould. Damp. Leave."
She detailed how when the children were born Elisabeth was left alone with nothing but an old book on childbirth, dirty scissors and a dirty mattress.
"Josef Fritzl used his daughter like his property," said Mrs Burkheiser.
In the first three years of Elisabeth's incarceration there was no hot water, shower or heating.
It was sometimes so hot that condensation dripped the down walls, she said.
She said: "It was bitingly cold in winter, blisteringly hot in summer. She had
to care for and feed babies here."
She added that among the worst aspects of Elisabeth's ordeal was "the uncertainty as to when he (Fritzl) would come down again, and rape before the eyes of the children."
And she told how Fritzl, the man who claimed he loved his second, secret family, cowed them all by saying the cellar was fitted with booby traps that would lead to gassing and electrocution should they ever mutiny and try to escape.
"But," added Mrs. Burkeheiser, "she would never have tried. Elisabeth Fritzl was a broken woman."
Ms Burkheiser, who is 32 and conducting her first major case since being made chief prosecutor, is pressing for life imprisonment in an institution for the criminally insane.
Rudolf Mayer, defending, appealed to the jury to be objective and not swayed by emotions. He insisted Mr Fritzl was "not a monster" and said his client even brought a Christmas tree down to his captives.
Right through Fritzl was able to hide his face from the battery of photographers who had assembled in the courtroom, using a large file. Reporters who were allowed to be present for the first few minutes were allowed to hurl some questions before the opening of the trial, but he studiously ignored them.
Prompted by the judge several times, Mr Fritzl today pleaded "partially" guilty to rape. Austrian law differentiates between the severity of rapes and levels of coercion, and takes into account the degree of violence used and the consequences for the victim.
Dr. Raoul Wagner, an eminent Viennese lawyer, warned that the charges have 'little chance of working to keep Fritzl in jail for life'.
But Wagner says: "I am convinced that after six-and-a-half-years he will be free again. The murder charge has no chance as the body was allegedly burnt and the ashes scattered in the garden.
'There is nobody and only Elisabeth's word over the details.
'The slavery charge has never been used since it was put on the books, and it does not really affect what happened here. He did not buy or sell his daugher in the slave trade, and the charges do not apply.
"At the most the incest and rape charge apply, and as sentences run concurrently, the most he would face would be rape - which means seven-and-a-half years with good behaviour, which with the year already spent inside means in six-and-a-half years he could be released.
"In a case like this the Austrian legal system is a nonsense. In America for 3,000 rapes a person would face 30,000 years in jail."
Constitutional expert Heinz Mayer warned: "If anyone were to raise an objection against the exclusion of the public then the whole proceedings might need to happen again."
Over the course of this week jurors will hear a tale of unparalleled horror; of 3,000 rapes, solitary childbirth in the darkness of a rat-infested cellar, beatings, humiliation and near-starvation endured by Elisabeth Fritzl.
Also during the course of the trial Austrian bureaucracy will have to give its version of events: why a convicted sex offender got away with his crimes for so long.
Social workers will have to answer why they entered his home 21 times and were never suspicious about him.