Taking the Measure of Relics of the True Cross

The relics displayed in the Church of the Holy Sepulcher in Jerusalem and Rome’s Basilica of the “Holy Cross in Jerusalem” are probably authentic.

The Holy Cross
The Holy Cross (photo: ACI Prensa Instagram / ACI Prensa Instagram)

Editor's Note: This was originally published in April 2011.

Whenever the subject of bogus relics comes up, you can count on someone saying, “There are enough pieces of the True Cross to rebuild Noah’s Ark!” Whoever delivers that punch line probably does not know that he or she is echoing the 16th-century Dutch humanist Erasmus, who, in a satire on pilgrimages, wrote, “So they say of the cross of Our Lord, which is shown publicly and privately in so many places, that, if all the fragments were collected together, they would appear to form a fair cargo for a merchant ship.”

Clearly, this is a punch line with a pedigree, but is it accurate? That would appear to be a difficult, if not impossible, question to answer. But in the last half of the 19th century, a French independent scholar named Charles Rohault de Fleury assigned himself the task of tracking down and measuring every surviving relic of the True Cross.

Weight and Volume

De Fleury, like almost all of his contemporaries, believed that Jesus carried the entire cross from Pontius Pilate’s palace to the summit of Calvary. (In the late 20th century, historians found that criminals condemned to crucifixion only carried the cross beam — the upright beam was erected and waiting at the place of execution.)

To estimate the weight of the cross Jesus bore, de Fleury drew upon studies of how much weight strong men in strenuous professions could carry: A robust porter, such as we see carrying the heavy baggage in old safari movies, could carry 200 pounds a distance of three miles in about an hour before needing a rest, while a brawny carpenter could carry 220 pounds of lumber on his shoulder 150 feet before stopping to unburden himself and rest. 

De Fleury calculated that the cross probably weighed about 220 pounds, but considering that Jesus dragged it rather than lifted and carried it, the weight to Our Lord would have felt like 55 pounds. Nonetheless, in his weakened condition after the scourging, even this modest weight was too much for Jesus, and so the Roman guards compelled Simon of Cyrene to help carry the cross.

Once he had estimated the weight of the cross, de Fleury calculated the size, or more accurately, volume, of the cross, which came to 10,900 cubic inches. But the total volume of all the fragments he had measured came to only 240 cubic inches. The number surprised him, so he made a generous allowance for fragments that were in private hands or otherwise had not come to his attention, as well as fragments that had been lost over the centuries or destroyed in war or during the vandalism of the Reformation. He multiplied his original number by 10 and arrived at a new figure: 2,400 cubic inches, not even a fifth of the estimated size of the cross upon which Christ was crucified.

In 1870, de Fleury published his findings in a book, Mémoire sur les Instruments de la Passion. De Fleury concluded that if all the surviving relics of the True Cross were somehow reassembled, there would not be enough lumber to crucify a man, let alone build Noah’s Ark. The 20th-century English Catholic author Evelyn Waugh, referring to de Fleury’s conclusions, said, “As far as volume goes, therefore, there is no strain on the credulity of the faithful.”

Discovering the Cross

Bishop Eusebius of Caesarea (c. 260-341) tells us that in about the year 327, Constantine, the first Christian emperor of Rome, wrote to St. Macarius, the bishop of Jerusalem, ordering him to tear down the Temple of Venus that stood on the site of Calvary and the Holy Sepulcher and build a basilica — at Constantine’s expense. Although Eusebius mentions that St. Helena, Constantine’s mother, was in the Holy Land at the time, he does not say that she was involved in the demolition-and-construction project, nor does he say that the excavators found the True Cross at the site.

Within 20 years of the construction of the Church of the Holy Sepulcher, however, the bishop of Jerusalem at the time, St. Cyril (c. 315-386), referred to the relics of the True Cross in a sermon, saying, “The whole world has since been filled with pieces of the wood of the cross.”

Archaeologists have discovered in the ruins of 4th-century churches in what is now Algeria inscriptions that declare these churches once held tiny relics of the cross. By the end of that century, Christian writers, including St. Ambrose, accepted as fact that it was Helena who found the True Cross.

According to an ancient tradition, beneath the Roman temple, excavators found three crosses, but nothing to distinguish the cross of Jesus from the crosses of the two thieves who were crucified with him. Helena had a dying woman carried to the site so she could touch each cross in turn. After touching one of the crosses, the sick woman was instantly healed, which was taken as a sign that it was the cross upon which Our Lord had died.

Veneration of the Cross

Helena took a portion of the cross back to Rome, where she had it enshrined in the chapel of her palace (now the Basilica of the “Holy Cross in Jerusalem”). The rest of the True Cross remained in Jerusalem, in a chapel attached to the Church of the Holy Sepulcher.

About the year 381, Egeria, a nun from Spain or southern France, made a pilgrimage to the Holy Land. In a lengthy letter to her religious community back home, she described her experiences. On the morning of Good Friday she joined a large congregation in the Chapel of the Holy Cross. After the bishop of Jerusalem had entered the sanctuary and taken his seat, the deacons carried in a silver casket and set it upon a table covered with a linen cloth. She wrote:

“The casket is opened and [the wood of the cross] is taken out, and both the wood of the cross and the titulus [the inscription Pilate had nailed above Christ’s head] are placed upon the table. Now, when it has been put upon the table, the bishop, as he sits, holds the extremities of the sacred wood firmly in his hands, while the deacons who stand around guard it. It is guarded thus because the custom is that the people, both faithful and catechumens, come one by one and, bowing down at the table, kiss the sacred wood and pass through. And because, I know not when, someone is said to have bitten off and stolen a portion of the sacred wood, it is thus guarded by the deacons who stand around, lest any one approaching should venture to do so again. And as all the people pass by one by one, all bowing themselves, they touch the cross and the titulus, first with their foreheads and then with their eyes; then they kiss the cross and pass through, but none lays his hand upon it to touch it.”

As early as Egeria’s day, a relic of the True Cross was coveted by Christians, which would lead in years to come to a host of false relics, some the product of outright fraud, others of wishful thinking. Today, it is virtually impossible to distinguish which relics of the cross are genuine, although the relics displayed in the Church of the Holy Sepulcher in Jerusalem and Rome’s Basilica of the “Holy Cross in Jerusalem” are probably authentic.