Royal School Armagh are to hold special prayers on Monday and counselling will be made available following the death of pupil John McCall in South Africa.
John McCall was destined for higher honours in the game
The 18-year-old collapsed during Ireland's opening game of the Under-19 Rugby World Cup in Durban.
He was rushed to hospital in Durban but died soon after.
"He was a natural leader to whom not only his own year group looked for
inspiration but the whole school," said headmaster Paul Crute.
Initial reports that he sustained an injury after the collapse of a scrum have been discounted.
The player is understood to have taken the ball at the tail of a line out and after he was tackled around the ankles, laid the ball back to his team-mates.
Play then moved on but the Irish player remained on the ground and then went into unconsciousness on the pitch.
He was pronounced dead two hours later at the St Augustine's Hospital.
A post mortem will be held in Durban on Tuesday to ascertain the cause of death.
Mr Crute, who visited the McCall family on Saturday night, said they were grief stricken.
"It is so difficult to take it in. He had his whole future ahead of him. It
is just so unexpected."
The family had a long association with the school, he added.
"He had received his entire education almost 14 years at the school as had
his sister and father. His brother James still attends the school.
"John was a young man of character, motivation and resolve, who was determined to make his mark in his chosen profession - he hoped to study
architecture at Queen's University - as well as his sport.
"It is tragic to lose a young man of his calibre and demeanour so young and
with such an outstanding future."
As details of the tragedy were relayed back to John's school, the Mr Crute
gathered together his staff for a pastoral team meeting.
John McCall lifting the Ulster Schools' Cup earlier this month
The school has provided special counselling for the teenager's classmates.
The player's father Ian, a well-known member of the Armagh rugby fraternity, travelled to Durban on SUnday evening to make arrangements to bring his son's body home to Northern Ireland.
The senior Ireland team were not informed of the tragedy until after their 37-16 Triple Crown victory over Scotland in Dublin.
His uncle Brian was a member of the Ireland squad that last won the Triple Crown back in 1985.
The teenager led Royal Armagh to victory in the Ulster Schools' Cup over Campbell College on St Patrick's Day - the same day he received his Ireland Under-19 call-up.
A decison on whether the Ireland Under-19 side will continue to play in the World Cup will be made on Monday.
A final decision on whether to continue wil be made by the Under-19 management and players in South Africa.
The Ireland team are scheduled to play Japan in the next match on Wednesday.
"For the moment the principal focus is on extending
sympathy and understanding to the McCall family and also the squad themselves, the management and players," said IRFU spokesman John Redmond who confirmed that senior vice-president Barry Keogh travelled to Durban on Sunday.
In another piece of irony relating to the school, back in 1927, Armagh also won the Schools', but the following season a player died on the field, and they withdrew from the competition until they re-entered back in 1965.