Life as a chorister in medieval cathedrals, collegiate churches and schools was hard. The singing boys lived under strict discipline and had to keep to a tiring daily routine. Living conditions were tough, without much food. Perhaps that was one reason why so much importance was given to one particular part of the Christmas celebrations - the reign of the Boy Bishop.

This custom was followed all over the Continent, but was especially important in England. It is connected with St Nicholas of Myra, the patron saint of children, who was very young when he was elected a Bishop. The election is also associated with Christ's advice to his followers to become like children if they wished to enter the kingdom of heaven. Pagan links exist too, namely with the pre-Christian festival of Saturnalia, also associated with this time of year, when people of high rank swopped places with the poor and humble.

A boy, usually a cathedral chorister, would be chosen to replace the Bishop over the Christmas period. In the beginning he was elected by the other choristers, but eventually the adult clergy would select him to ensure they had some control over his brief reign. In England, the Boy Bishop, or Nicholas Bishop as he might be called in other places, was elected on 6 December, the feastday of St Nicholas. His reign ended on 28 December, the feastday of the Holy Innocents, who were the male children of Bethlehem slaughtered by Herod in his attempt to kill the Child Jesus.

The investiture of the Boy Bishop was a solemn occasion. As the Magnificat prayer was recited, the Bishop would step down from his chair of office at the line "He hath put down the mighty from their seat", and was then replaced in it by his boy successor as the phrase continued "and exalted the humble and meek". The boy would be dressed in full bishop's robes, mitre and crozier included. Attended by other boys dressed as priests, he would then process around the town, giving his blessing to the people. In York, he and his attendants would be required to visit every parish in the diocese. Often the Boy Bishop had the authority to collect revenues from church officials in these parishes.

For the length of the Boy Bishop's reign he and his boy priests would control the cathedral, with adult clergy replacing them in their regular duties. He could order holidays and treats for the choristers, and give out sweets and presents. In some areas, tokens survive that were given out by Boy Bishops to the poor, who then exchanged them for food and drink in local shops. At Salisbury, the Boy Bishop was said to have the power to decide which priest or rector was given jobs that became vacant while he was in his post. There is a monument to an unnamed Boy Bishop in Salisbury Cathedral, which suggests that he also had the right to a bishop's funeral if he died during his reign.

As well as these privileges, the boy bishop had the authority to carry out all the religious ceremonies of the Church, which he would have had to learn about before taking up his role. The only thing he was not allowed to do was celebrate Mass. He would be required to preach one sermon, on the feastday of the Holy Innocents, when he and the boy priests carried out the religious ceremonies on their own. The adult clergy would usually write the sermon for him. Only three of these sermons survive, including one preached at Gloucester, which blames parents and schoolmasters for the bad behaviour of children and young people. After the service, he would end his reign by calling at homes with his attendants to sing songs and give blessings. They would be repaid with entertainment and gifts of money and food, which were sometimes distributed to the poor, and sometimes to the choristers.

With more and more crowds attracted to cathedrals by this custom, the election of the boy bishop spread to parish churches with enough choristers to make it possible. Over time, the celebrations became associated with a lot of disorderly behaviour: one Boy Bishop was murdered after a riot in Paris. In 1542, during the Protestant Reformation, Henry VIII banned the Boy Bishop tradition in England on the grounds that it distracted people from their prayers. In 1552 Mary I restarted it as part of her campaign to restore Catholicism to England. Eventually it was abolished during the reign of Elizabeth I.

Some parts of England have revived the tradition since, for example Salisbury Cathedral, Hereford Cathedral, Westminster Cathedral in London, and the parish church of Claines in Worcestershire. On the continent, the Council of Basle suppressed the tradition in 1431, though it survived longest in Germany, where it was thought to have been instituted by Pope Gregory IV. The last recorded election of a German Boy Bishop was in 1799, in the town of Meiningen.