The Catholic author Joan Carroll Cruz, who died in 2012, wrote about the phenomenon in her 1977 book “The Incorruptibles.”

She identified 102 saints or blesseds who are recognized by the Church to be incorrupt.

She said there were certainly many more, but these 102 are “the great majority, and certainly the most famous.”

Cruz did extensive research for her book and, because she was writing before the internet, corresponded with the shrines holding the bodies to authenticate their incorruptibility and to discover if they had been embalmed.

More in Vatican

She noted that at the time she was researching and writing, there were errors, or “false rumors,” about the incorruptibility of some saints.

The poor quality of some photographs of saints’ remains sometimes have lead people to believe that the “simulated figures” holding the relics of saints were really unnaturally preserved corpses, she wrote.

An 18th-century pope gave his definition of incorruptibility in a treatise on the process of beatification and canonization of saints.

Prospero Lambertini, the future Pope Benedict XIV, wrote the lengthy work while serving in the Holy See’s congregation for the promotion of saints’ causes from 1708 to 1728.

Two chapters of the book, titled “De Cadaverum Incorruptione,” outlined the young theologian and lawyer’s position on the phenomenon of incorruptibility.

According to Cruz, Lambertini ruled “that the bodies of saintly persons that are found intact, but disintegrated after a few years, could not be considered miraculous preservation.”

“The only conservations he was willing to consider extraordinary are those that retain their lifelike flexibility, color, and freshness, without deliberate intervention, for many years following their deaths,” she noted.

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Cruz’s book documented cases where this has happened, such as for St. John of the Cross, who died in 1591 and whose body, she wrote, “is still perfectly supple.”

More recent saints have also exhibited this phenomenon, such as St. Charbel Makhlouf, a Lebanese monk who died in 1898. 

Miracles also occurred around the time of St. Charbel’s exhumation from his dirt grave, a few years after his death. One was the presence of a fragrant scent, a common phenomenon with incorruptibles. A bright light also emanated from St. Charbel’s grave after his death, prompting devotees of the holy monk to ask for his remains to be examined.

Common objections

A common objection to incorruptibility is the idea that the body either must have been deliberately preserved, a practice since ancient times, or that the conditions of the grave or tomb allowed for natural preservation.

In at least one case, modern scientific examination has found that a saint previously believed to be incorrupt was likely not.