A former head teacher, his brother and a care worker have been convicted of cruelty against children at a special school between 1975 and 1988.
Brothers Anthony and George Robson convicted of child cruelty
A fourth man, now dead, had been charged with indecent assaults.
The four worked at the Banham Marshalls College near Diss, Norfolk, which is now under different ownership.
George Robson, former head teacher, and his brother Anthony were convicted at Norwich Crown Court. Care worker David Clarke has already been sentenced.
Details of the case emerged after Norwich Crown Court lifted reporting restrictions imposed because of undisclosed legal arguments around the trial which was held two years ago.
The court heard that two boys at the school for vulnerable children with special needs were forced to fight in front of all the other pupils and staff.
One boy was told to eat his own vomit and another had to destroy all his own birthday presents as punishments.
Children who stayed overnight at Leslie Beckett's home were abused.
The investigation into child cruelty allegations at Banham Marshalls College, formerly The Old Rectory, was launched in February 2003 following an inspection by the then National Care Standards Commission (NCSC).
George Robson, 66, of Old Rectory, The Street, Bridgham, Norfolk, was found guilty of five counts of causing cruelty to children.
Anthony Robson, 63, of Mill Road, Banham, Norfolk, was convicted of three counts of child cruelty in May 2005.
Both men will be sentenced at a later date.
Care worker David Clarke and Leslie Beckett faced charges
Care worker David Clarke, 56, of Mill Road, Banham, Norfolk was convicted of four counts of child cruelty in October 2005 and was earlier given a 12-month suspended sentence which he has served.
Leslie Beckett, born in 1915, late of Pilgrims Way, Harleston, Norfolk, was charged with 13 counts of indecent assault on children, but died before he could come to trial.
Detective Inspector Matt Sharman who led the inquiry said: "This has been a long and involved investigation looking into events that took place up to 30 years ago.
"The many victims in the case, some of whom had never come to terms with what happened to them at the Old Rectory or Banham Marshalls College, were traced to addresses all over this country and even abroad. "
"The school was clearly run in a climate of fear with 'control' of the children being of paramount importance."
The investigation, conducted by officers specialised in child protection issues, had the support of Norfolk County Council's Children's Services and the NCSC, now the Commission of Social Care Inspection.