Mohammed bin Salman, Crown Prince of Saudi Arabia, visited London for three days recently. He and Theresa May’s government had a lot to talk about—trade, terrorism, oil prices, women’s rights. It was a busy if predictable agenda. The most interesting topic came up when the Crown Prince paid a call on Justin Welby, Archbishop of Canterbury. It is the type of photo op visit that most dignitaries make when visiting a foreign country. But Archbishop Welby caught everyone off guard when he departed from the polite chit-chat and asked the prince to do something the Saudi royal family has refused to do since the founding of their dynasty in 1744: The archbishop asked that King Salman lift the ban on the free practice of Christianity in his kingdom and permit Christians to construct churches.

After the meeting, the archbishop’s spokesman said that in reply to the archbishop’s appeal, the Crown Prince “made a strong commitment to promote the flourishing of those of different faith traditions, and to interfaith dialogue within the Kingdom and beyond.”

On other words, his answer to Archbishop Welby is, “No.”

In fairness, Saudi Arabia is not targeting Christianity. It does not permit any religion to build a house of worship in the kingdom. Technically, it does not permit any non-Muslim religious services, but on this point government officials are willing to turn a blind eye as long as there has been no advertising of the service—and the ban on advertising extends even to posting a notice on a bulletin board. The place where the service is held must be obscure. The place cannot be permanent, even if it is a sacred place. For example, we have American troops stationed in Saudi Arabia—that has been the case for years. Yet chaplains cannot have a room or even a tent to use as a chapel because under Saudi law it is considered a permanent location.

The Saudi royal family takes this prohibition very seriously because Mecca and Medina, Islam’s two holiest cities, are both located in Saudi Arabia. As guardians of these sacred sites, the royal family believes non-Muslim houses of worship in the kingdom would be offensive to Muslims. And who, knows, maybe it would.

The appeal from the leader of the Anglican Communion is not the first to be addressed to the House of Saud. In 2008 Pope Benedict XVI sent his most senior expert on Middle Eastern affairs, Archbishop Paul-Mounged El-Hashem, to Saudi Arabia to discuss a reversal of this policy the granting at last of permission to erect Christian churches. At the time it was estimated that between 3 and 4 million Christians reside in Saudi Arabia, a figure which probably has not changed much today. Most Christians come from the Philippines, India and Latin America. They tend to work as laborers, or as housekeepers, or as nannies for well-to-do Saudi families. Yet nothing came of Archbishop El-Hashem’s mission.

Father Randall Roberts experienced the constraints the Saudis place on non-Muslims when he served as a chaplain during Desert Storm. He was stationed at a base in Riyadh. He was surprised to find so many Catholics in the Saudi capital, but he could not minister to them. In an effort not to offend an ally, it was U.S. government policy that Catholic chaplains could administer the sacraments, say Mass, and lead other liturgies only for American military personnel. Foreign workers could not even pray the Rosary with the troops.

Father Roberts was not pleased that he had to turn away Catholics who desired the Mass and the sacraments. And he found the makeshift circumstances he and the troops had to endure irksome. The place he found to say Mass was sufficiently obscure to satisfy the authorities—it was an abandoned recreation center. Actually, it was a ruin. One of the walls had collapsed, although the three that remained were enough to hold up the roof. Around this shack was a chain-link fence. He described the arrangements in a little book of vignettes written by military chaplains called Blessings from the Battlefield: “A Mass kit sits atop a pool table, and officiating is a young priest in camouflage battle dress with only a stole around his neck. Hardly a prestigious setting for the Eucharist.” Yet the Mass was well-attended, thanks to the Catholic grapevine. Remember, no advertising. Word-of-mouth is the only permissible method for getting the word out of where and when Mass will be said.

On one occasion, as Father Roberts was saying Mass in the ruin, he saw a Filipino man walking by. The man glanced over and realized Mass was being said. Then the priest saw something extraordinary. “The young man was pressing himself against [the fence]. He appeared to be straining his whole body—or at least his heart—through the chain-link fence, like water through a filter, to make himself more present at a holy ritual he sorely missed and cherished. The sheer ecstasy on his face from being present at the Holy Sacrifice of the Mass—though he was unable to move any closer—is an image that will be indelibly etched on my heart until I die.”

I’m sure we all understand completely how natural it is that Father Roberts wanted at least a suitable altar and vestments. It is the bare minimum. But then along comes this Filipino Catholic who by Saudi law and U.S. policy is denied access to the greatest thing that feeds the soul. And suddenly you realize that even in wretched circumstances, the bread and wine will still become Christ’s Body and Blood. No king has ever been able to stop that.