In May 1277, the recently-elected Pope John XXI died at his palace at Viterbo. His death was unexpected, not least to the pontiff himself, who had repeatedly and very publicly claimed that he knew how to prolong his life by many years – only to be crushed when a ceiling fell on him. Nevertheless, it was important that the proper ceremonies on the death of a pope were followed. Despite his fatal injuries, his corpse was publicly displayed before his burial, which took place six days later.

Today, the public display of a pope’s remains at the heart of the papal funeral ritual, but when John XXI died it was a relatively new innovation. Indeed, public display of the papal corpse seems to have become common only a century earlier; before this, rapid burial (often on the day of death) was the norm, with the election held three days later. Even in the 13th century, most popes seem to have been displayed for a matter of hours, and buried the following day. Then, in the 1270s, things began to change. Gregory X (1271-76) promulgated the constitution Ubi periculum (‘Where There is Danger’), which established the modern conclave and required the cardinals to hold an election within ten days. In doing so, he created the lengthy mourning period that is still observed today.

By the late 14th century, the novena (a nine-day period of funeral ceremonial) had become the norm, and the display of the corpse was at its centre. Preparations began almost immediately after the pope died: his body was washed and dressed in ‘sacred vestments, almost all of red’, as if he was going to celebrate mass, and laid on a mattress of red silk, atop a bier decorated with gold cloth and the papal arms. It was then taken to a chapel, where it could be viewed by a select audience, before being carried to the church where it would be displayed for several days before a public funeral.

These new forms of display provided a host of benefits to an increasingly powerful institution, and though a big send-off undoubtedly honoured the dead man, it also reasserted the power and prestige of the Church he represented. It was no coincidence that new papal rituals emerged at the same time as the French and English monarchs began to be buried with increasing pomp, nor that the new mourning period was the same length as that which honoured a Byzantine emperor.

Highly-formalised burial rites also helped to ensure the proper transfer of power, not least because the very public display of a pope’s remains provided firm proof that he was dead, and that it was therefore appropriate for a new pope to be elected. If a pope was elected too hastily, then his authority could be questioned – a problem which plagued the reforming Pope Gregory VII (d. 1085), whose critics insisted that he had been elected ‘even before the body of his predecessor had been buried’, just as some conservatives refused to accept Pope Francis’s election during the lifetime of Benedict XVI.

Such changes posed practical challenges – especially as they coincided with a period in which the Church developed a growing horror of decay, and in which bodily incorruption was widely seen as a sign of sanctity. For centuries, it had been customary for a papal corpse to be washed and dressed in preparation for its burial, but now more sophisticated attempts at preservation became necessary. By the 14th century, the washing of the corpse was usually followed by a complicated process of embalming, in which an apothecary would ‘close all his apertures tightly with wool or flax [and pack] the anus, mouth, nostrils and ears with myrrh, incense and aloe’, before filling the throat and nose with ‘aromatics and especially with wool’, and rubbing the whole body with balsam. In certain cases, a more intrusive procedure was performed: experts such as Pietro Argellata (the Bolognese professor of surgery who embalmed Alexander V in 1410) were confident that, by removing the internal organs, they could preserve a corpse sufficiently well to allow it to be displayed for a whole week.

Unfortunately, not all embalmers were as skilled as Argellata, and things could and did go wrong. When Alexander VI died in 1503, his face gradually turned black and swollen, providing ‘such a horrible spectacle that everyone said they had never seen anything like it’. Nor was decay the only problem created by the new customs; there were also fears about how the corpse would be treated during the lying-in-state. Most mourners acted with appropriate decorum, weeping and praying for the dead man’s soul. Others asked for his intercession, and received healing miracles. When Martin IV’s corpse was displayed in Perugia cathedral for several days after his death in March 1285, the faithful prostrated themselves around the bier and ‘people afflicted with various maladies, especially of sight, joints, hearing and speech’ were cured.

From an ecclesiastical perspective, such dignified devotions enhanced the reputation of both the deceased and the institution he represented, and were thus to be encouraged. But some medieval Christians were a little too keen to get close to the holy dead. When Lanfranc, Bishop of Pavia (d. 1198) lay in state in his cathedral, one pious old woman ‘hobbled in through the screen, took his hand, and blessed herself’. Elsewhere, mourners keen to obtain a relic of a potential saint removed jewellery and pieces of clothing; some even cut off body parts such as nails and hair. It was partly to prevent such undesirable behaviour that the corpse of Sixtus IV (d. 1484) was displayed with ‘the feet sticking out of a closed iron grate… [so] that those who wanted to could kiss them’, but the rest of the body was out of bounds and heavily guarded.

Unfortunately, the attendants employed to look after medieval papal remains seem to have been less trustworthy than the modern Swiss Guards: in 1503, when Alexander VI died, his corpse was carried to the Chapell of the Febbri by ‘six very crude men who joked and cursed the pope and his corpse’, before covering the coffin with an old rug. His successor Julius II, having heard terrible stories of popes ‘left lying there in a shameful way, downright nude with their privates parts exposed’, bribed his master of ceremonies to ensure that he would be treated with due reverence. Though modern mourners can’t always be trusted to behave appropriately – as this week’s complaints about selfie-takers have shown – modern popes can at least expect to be treated with rather more respect than their medieval counterparts.