A former teacher told a girl's parents she needed extra help at school as a ruse to allow him to groom her for sexual abuse, a court has heard.
Bernard Haunch, 72, is alleged to have subjected the girl to repeated sex attacks while he was a "senior and respected" teacher at a rural school.
At the small school in West Sussex, French teacher Haunch conducted abuse on the girl and a boy in the 1970s and 1980s, breaching the trust placed in him, Lewes Crown Court heard.
Opening the Crown's case, prosecutor Richard Barton said the girl kept the abuse secret for decades until finally disclosing it to relatives two years ago.
He said: "It's the Crown's case that throughout his adult life, he has been a paedophile and that he used his position as a teacher to have sexual contact with young pre-pubescent children."
The grooming process began after Haunch, of Marlins Close, Sutton, south London, told the girl's mother she needed extra help with her schooling, it was said.
Mr Barton said: "It's the Crown's case that this was a lie that he used as a ruse to allow him to take the girl up to his room so she was able to repeatedly visit him on her own.
"It's the Crown's case that at no stage did he give her extra tuition. Instead, over the months and years, he gradually groomed her."
Haunch offered praise, threats and rewards to the girl, who cannot be named, and at one point threatened to kill her parents if she ever disclosed what had happened, jurors heard.
Mr Barton said Haunch would ask the girl to play different games with him, all of which had a sexual theme, including doctors and nurses.
In what was described as the most serious incident, it is alleged that Haunch invited the girl to the school chapel where she was repeatedly sexually assaulted by different men while he looked on.
Following his arrest, Mr Barton said Haunch gave an "audible gasp" when the girl's name was revealed by an officer but that he denied responsibility for her claims.
He did, however, concede to police a "very serious error" with a boy pupil which led to his dismissal.
Mr Barton said the boy was traced by police and he told officers he was abused by Haunch.
The court heard that following his sacking, Haunch wrote a letter to the boy's parents telling how "ashamed" he was but the case was not referred to the police at the time.
Haunch denies 16 offences, including rape and indecent assault between June 1975 and September 1983.