The offending was categorically denied by the accused and by his wife, who took the stand and told the court that as a practising Catholic she had taken a vow to tell the truth.
During the trial Crown prosecutor Steve Manning told the jury the fact the incidents had occurred a long time ago made them "no less important to the woman who alleges today that they happened".
"She simply wants her day in court and wants to be believed," he said.
It took the jury of six men and six women just 45 minutes to find the man guilty of one count of rape and two of indecent assault.
The current maximum sentence for rape is 20 years' imprisonment, however the man was sentenced under legislation relevant to the 1970s, when the offending occurred, which carried a maximum of 14 years' imprisonment.