Patrick Harte (80) is facing trial on 90 charges of indecently and sexually assaulting boys over a 28-year period.
He was granted bail despite garda objections, after Dublin District Court heard he denied all the allegations.
Judge Alan Mitchell set cash bail at €30,000, with "very strict conditions" and adjourned the case to later this month for the preparation of a book of evidence.
Mr Harte, of Glendown Park, Templeogue is accused of 83 counts of indecent assault, one attempted indecent assault and six sexual assaults on 20 alleged victims on dates between 1967 and 1995.
He first appeared in court on the charges last month and his case came before Judge Mitchell today for a bail application.
Objecting to bail, Detective Garda Colleen Gallagher of Kevin Street station cited the seriousness of the charges and her belief that the accused was a “serious flight risk.”
She said all the alleged victims were previous pupils of Sancta Maria Christian Brothers primary school on Synge Street in Dublin, where Mr Harte was a member of staff between September 1967 and August 2007, in the roles of teacher and principal.
When questioned, he denied all the allegations as they were put to him, Det Gda Gallagher said. The evidence in support of the charges included 20 statements of complaint and the alleged victims had presented as “extremely credible witnesses,” she continued.
The allegations were similar in nature and indicated “prolonged, systematic abuse” by Mr Harte at the school. Det Gda Gallagher said.
The alleged victims were unknown to each other as they were in different years or classes. Roll book evidence would confirm their presence in the school at the time of the alleged abuse. Some 219 ex-pupils were spoken to in the investigation, 72 witness statements were taken and it was alleged the abuse was in the presence of the entire class, the court heard. There were a number of independent witnesses.
Det Gda Gallagher believed if granted bail, Mr Harte would be unwilling to remain in this jurisdiction and would attempt to relocate.
Applying for bail, defence barrister John Griffin said the garda was basing her objection on a belief with “no hard evidence” that the accused would “flee off to Dublin airport and take the first flight out of here.”
He said bail was being objected to “simply because he is facing a number of criminal charges on which he has a presumption of innocence.”
"It's speculation and assumption, that's all it is," Mr Griffin said.
Mr Griffin said the accused was an 80-year-old man in ill health with long term cardiac issues. There was no concern that he would intimidate any witnesses.
The court heard Mr Harte, whose wife died in 2008, was originally from Sligo and had two adult daughters, extended family and a wide circle of friends.
The accused's pension income was €35,000 per year.
Judge Mitchell said he had to balance the seriousness of the charges against the accused’s presumption of innocence. He granted bail in the sum of €15,000 cash and an independent surrey of €15,000, also in cash, with “very strict conditions.”
Under the terms, Mr Harte must live at his home address, sign on three times per week at Terenure garda station, have no contact directly or indirectly with any alleged victims or witnesses, surrender his passport, not leave the country and be contactable by phone.
The case was adjourned to June 24.