A 42-year-old man has appeared at Londonderry Crown Court charged with three counts of molesting and 15 counts of indecently assaulting a young girl.
The offences were alleged to have happened in Derry between May 1995 and May 2004 starting when the girl was six.
The man, whose name cannot be released for legal reasons, now lives in the Republic of Ireland.
He denies all the allegations against him.
Opening the prosecution case, prosecutor Philip Mateer QC said the allegations related to the sexual abuse of the young girl while she was in the care of the defendant.
He said the case was that the defendant repeatedly and regularly subjected the girl to a series of sexual assaults at two addresses in Derry.
The opportunity for the abuse arose, he said, when the defendant's wife worked night-shifts.
On occasions the defendant mixed alcoholic drinks for the girl and gave them to her to drink.
The defendant was questioned by the Irish police after the alleged victim outlined her accusations to the police in 2009.
He said the defendant was interviewed by the Irish police, and denied all the allegations.
The trial continues.