Dr. Thomas Arnold, headmaster of Rugby from 1828 to 1841, defined fagging as the power given by the supreme authorities of the school to the Sixth Form, to be exercised by them over younger boys. Older pupils, in a sense trustees, would take responsibility for the behaviour of younger boys, thus helping the staff to avoid chaos. Fagging was a fully established system at Eton and Winchester in the 16th century, and is probably a good deal older.
During the 19th century, almost all English public schools adopted a fagging system.
The right to fag carried with it certain well-defined duties. The senior, called fag-master, also known as the protector of his fags, was responsible for their happiness and good conduct. In cases of bullying or injustice, their appeal was to him, not to the form-master, or house master, and, except in the gravest cases, all incidents were dealt with by the fag-master on his own responsibility and without report to the master.
The duties undertaken by fags, the time taken, and their general treatment, varied widely. Each school had its own tradition. Until circa 1900 a fag's duties included such humble tasks as blacking boots, brushing clothes and cooking breakfasts, and there was no limit as to hours. Almost all the fag's spare time could be so monopolized. Later, fagging was restricted to such light tasks as running errands, bringing tea to the masters' study and fagging at cricket or football. At many schools, fag-masters were expected to reward their fags for their efforts at the end of term by giving a monetary 'fag tip'.
The 1911 Britannica details an evolution of the role at Eton college. Roald Dahl relates in his autobiography being told, as a fag, to warm toilet seats for older boys at Repton. Stephen Fry describes a practice similar to fagging used as punishment.
At The Leys School, Cambridge, fagging had ceased completely by 1966.