DENVER, Colorado – There’s an old Latin phrase that’s suddenly new again – at least in the realm of Catholic Twitter™.

The resurgence of the the Latin phrase “memento mori” (remember your death) is thanks in large part to tweeting nun Sister Theresa Aletheia, a “media nun” with the Daughters of St. Paul, who has been recording, via tweets, what it’s like to have a (plastic) skull sitting on her desk:

The phrase, and practice, has caught on, and a quick Twitter search of #mementomori now reveals hundreds of results.

But even before nuns and Catholic millennials were tweeting about the skulls on their desks, religious orders have been “memento mori”-ing for centuries. Here’s how various religious orders have kept their mortality in mind throughout the ages.

Origins of the phrase

According to legend, the phrase “memento mori” may have originated with the Roman empire. Allegedly, when victorious Roman generals returned from battle, in the midst of their festivities, a slave or another low-ranking citizen would follow them around and whisper “memento mori,” or some other reminder that their earthly glory was temporary.

Even before the Roman empire, meditation on death and the last things was a common practice of ancient philosophers like Plato, who once said that philosophy was “about nothing else but dying and being dead.”

The phrase and the practice was then incorporated into medieval Christianity – death was especially poignant as the plague spread throughout Europe and Asia, killing millions of people within the span of just a few years.

“Memento mori” was such a popular religious theme in this period that it inspired a genre of art, music and literature.

Memento mori myths and the Brothers of the Dead

One of the most common myths surrounding “memento mori” is that the phrase is used by monks, particularly the famously-ascetic Trappist monks, as a form of greeting among brothers.

Trappist Father Timothy Scott said that this myth originated with a now-obsolete order of French monks called “The Order of the Hermits of Saint Paul,” who came to be known as the “Brothers of the Dead.”

According to “La Sombre Trappe,” by Father M. Anselme Dimier, this order “pushed its tastes for the macabre to the extreme,” wearing scapulars with skulls and crossbones, and kissing a skull at the foot of the cross before each meal.

The words “Memento Mori” were found on the seal of the order alongside a skull and crossbones, and skulls were prominently displayed in most parts of the monastery, including in each brother’s cell.

The brothers of this order were also known for greeting each other with “Think of death, dear brother,” and rumors have spread that the Trappists adopted this tradition, even after the Brothers of the Dead were suppressed by Pope Urban VIII in 1633.

“In no period of the Order’s history, in no Trappist monastery, have these words been in usage; the brothers greet one another in silence, as in the early days of the Order of Citeaux,” Dimier wrote.

Scott confirmed that a silent greeting “is the constant tradition and practice of the Order.”

How Trappists “memento mori”

Trappists are a branch of Cistercian monks, a reformed branch of the Benedictines, who desired to live the Rule of St. Benedict more authentically.

But while Trappist brothers don’t use “memento mori” as a greeting, other reminders of death have been present in the Trappist order, particularly in older monasteries, Scott said.

In his book A Time to Keep Silence, Patrick Leigh Fermor recalls these symbols of death, particularly present in Trappist monasteries during the 18th and 19th century.

“Symbols of death and dissolution confronted the eye at every turn, and in the refectory the beckoning torso of a painted skeleton, equipped with an hourglass and a scythe, leant, with the terrifying archness of a forgotten guest, across the coping of a wall on which were inscribed the words: ‘Tonight perhaps?’”

Scott added that he has heard of several other monasteries with various “memento mori” traditions, such as the monastery of la Val Sainte in Switzerland, which kept a white-wood cross and a skull in the middle of the refectory, or dining hall. Another Trappist monastery in France had the words “Hodie mihi, cras tibi” (Today I die, tomorrow it will be you) written above the door leading to the cemetery.

These skulls, inscriptions, and the various prayers for the dead help the brothers “to keep in mind that our time on this earth is limited and what we do now matters for eternity,” Scott said.

“We will be accountable one day before God for all that we do. It makes no sense to waste the precious time that has been allotted to us. We must use it to do good and to love others now.

“However, the theme of memento mori, remembrance of death, needs to be set within the larger theme of the memory or mindfulness of God,” he added. “The monastic life is oriented primarily toward cultivating a living relationship with the persons of the Trinity, Father, Son and Holy Spirit, who have been revealed to us in the Son, Jesus Christ, and who, through his passion, death, and resurrection have called us to full communion and fellowship with them now and in eternity.”

The bone churches of Europe

Several orders of monks, including the Capuchins, Franciscans, and the Cistercians, are also known for having built churches or crypts decorated almost exclusively with the remains of their forebearers, a stark “memento mori” for any visitors to these sites.

One of the best-known such churches, sometimes called an Ossuary, is the Capuchin crypt beneath the church of Santa Maria della Concezione dei Cappuccini on the Via Veneto in Rome, Italy, which includes six chapels, five of which are covered in the skeletal remains of Capuchin friars of yesteryear.

The crypt was built in the 1630s, when Pope Urban VIII ordered some Capuchin friars to set up residency at the Church, and asked that they bring the remains of their bygone brothers with them, so that they would not be abandoned.

In total, an estimated 4,000 skeletons, from friars deceased between the 1520s – 1870s, decorate the insides of the various chapels. The various crypts include a crypt of the resurrection, a crypt of skulls, a crypt of leg and thigh bones, and a crypt of pelvises. A plaque in one display in the crypt reads: “What you are now, we once were; what we are now, you shall be.”

Allegedly, this Roman ossuary inspired a similar “Bone Church” in Prague, in the Czech Republic. There, the Sedlec Ossuary, built by Cistercian monks, is decorated with the remains of an estimated 40,000 people.

The reason for the large number of remains dates back to the 1200s, when a Cistercian monk returned from a pilgrimage to the Holy Land, where he brought back dirt from Golgatha, the hill where Christ was crucified, and sprinkled that dirt in the cemetery at the monastery.

As word of this holy dirt spread, the cemetery became a popular place in which to be buried. By the time the plague hit, the number of people requesting burial in the cemetery became so great that the monks began exhuming the bones, storing them in the church, and using them for interior decoration.

The church has been restored several times and is no longer in possession of the Cistercian order, but the popular site receives thousands of visitors annually.

A third popular “Bone Church” is the Capela dos Ossos, in Évora, Portugal, next to the Church of St. Francis.

Built by a Franciscan in the 16th century, the chapel has similar origins to the Czech Ossuary, in that it became a creative way to store the bones contained in cemeteries running out of room to house remains.

Reportedly, the monk also believed that the Church could be a force for the Counter-Reformation, and a good place for Catholics of the area to come and remember their mortality.

Like the Roman ossuary, the bone church in Portugal has several “memento mori” themed inscriptions, including Ecclesiastes 7:1 “A good name is better than good ointment, and the day of death than the day of birth.”

Dominicans – the best order in which to die

For Dominican friars, their “memento mori” comes every day when they recite prayers for the dead, said Father Aquinas Guilbeau, professor of moral theology for the Pontifical Faculty of the Immaculate Conception at the Dominican House of Studies.

The Dominicans pray for the dead so frequently that it’s become part of a joke, he told CNA.

“There are many reasons you want to live in the other orders – the Benedictines, the Franciscans, the Jesuits – but out of all of them, you want to die with the Dominicans, because we constantly pray for the dead,” he said.

Whenever a Dominican friar dies, all the priests in his province celebrate a Mass for him. The order also prays what is called the “De Profundis” – a daily prayer, typically before a main meal, that includes praying Psalm 130 in remembrance of all of the men of the province whose death anniversary is on that day.

Dominicans also celebrate an additional “All Saints Day” and “All Souls Day” –  they celebrate these feasts with the Church on Nov. 1 and 2, but then they celebrate a second round of these feasts on Nov. 7 and 8, particularly praying for the Dominican saints and souls.

“In terms of praying daily for the dead, it is a constant reminder of our own mortality, that heaven and eternal life is the goal, and it’s also a reminder that death is something that we all face,” Guilbeau said.

“When we die, we go alone, there’s no one who accompanies us in that at that moment. But by praying for those who have gone before us in death, we get a sense of that union and community that endures into the next life, and insofar as we aid the dead by our prayers, they’re waiting for us and aiding us by their prayers. It’s a daily reminder of the common prayer that we have for each other.

“In terms of…sleeping in our coffin or having skulls on the desk, we don’t do that,” Guilbeau said, but he added that the black cape that Dominicans wear is meant to serve as a physical “memento mori” for the order.

The daily reminder of death isn’t something “macabre or depressing,” Guilbeau added, “but it’s something hopeful and joyful, that this veil of tears is not the end of our existence, it’s not the goal.

“If we live in the love of Jesus Christ and we live in the light of the Holy Spirit, there’s constant preparation  and help and grace and strength for that moment when we pass from this life to the next,” he said.

Therefore, for the saint, death isn’t something to be feared, but welcomed and embraced like a sibling, Guilbeau said, recalling the words of St. Francis who once wrote in his “Canticle of the Sun”: “Praised be You, my Lord through Sister Death, from whom no-one living can escape. Woe to those who die in mortal sin! Blessed are they She finds doing Your Will.”