The children's bodies were found piled into a septic tank at the back of a place called The Home, where the kids of unmarried women would often be dumped.
Between 1925 and 1961, thousands of women and their children passed through The Home, which was run by nuns.
'To get pregnant out of marriage was the worst thing on Earth. It was the worst crime a woman could commit, even though a lot of the time it had been because of a rape.'
At the time, being unmarried and pregnant carried massive societal and religious stigma.
'When daughters became pregnant, they were ostracised completely,' says local historian Catherine Corless, who discovered the origins of the mass frame in some never before seen documents.
'Families would be afraid of neighbours finding out, because to get pregnant out of marriage was the worst thing on Earth. It was the worst crime a woman could commit, even though a lot of the time it had been because of a rape.'
According to Corless' documents, most of the children died of malnutrition and neglect, or of disease such as measles, TB, gastroenteritis and pneumonia.
And according to report published in 1944, children of The Home were 'emaciated…pot-bellied…fragile' compared to other children in the town.
Corless added that schoolboys had stumbled across the mass grave, which lies beneath a cracked piece of concrete.
'The boys told me it had been filled to the brim with human skulls and bones.'