A 65-year-old man who was extradited from County Donegal was sentenced to five years in prison and ordered to sign the sex offenders register for life after he pleaded guilty to 25 sexual abuse charges and two counts of assault.
He also admitted assaulting his ex-wife on two different occasions.
The man who cannot be named for legal reasons appeared at Derry Crown Court where he admitted 19 charges of indecent assault and six charges of gross indecency against his daughter and niece which took place between 1970 and 1981.
He also admitted he had also physically abused his wife, burning her on the back with a cigarette and throwing her down the stairs.
The court heard the assaults on his daughter began in the summer of 1978 when she was aged 12 an continued until she was aged 15.
They began when the girl's mother got a job that entailed her working nights.
The assaults took various forms and Ms Jackie Orr QC for the Crown said they were a 'regular and ongoing occurrence.'
The injured party told police that after they occurred she felt 'really horrible and shivered with fear and cold.'
The court heard that after each occurrence the man would apologise and say it would not happen again.
The assaults on his niece began when the girl was aged around 5 and continued until she was aged about 11. It was said that these assaults occurred when both parties were fully clothed.
Judge Des Marrinan said that the man had deprived his child and his niece of their innocent childhood.