After one trip into Libya as a migrant worker, Tawadros Youssef Tawadros reported that he had been warned that his Christian name -- "Theodore," in English -- might anger Muslim radicals.

His widow, Maleka Ayad, recalled him saying: "Anyone who starts changing his name will end up changing his faith."

Malak Ibrahim Seniut was more blunt, in a final talk with his priest. Told that Christians could be witnesses by living long, faithful lives, the young man replied: "That's not enough for me. I want to do it through death."

On Feb. 15, 2015, both were among the men beheaded by Islamic State soldiers on a beach in Libya. All 21 -- 20 Egyptian Copts and a Ghanan who professed his Christian faith -- were soon declared martyrs by the Coptic Orthodox Church. This is the latest chapter in a long drama, detailed by writer Martin Mosebach, of the German Academy of Arts.

"The Coptic Church, founded by St. Mark the Evangelist, is among the earliest manifestations of Christianity. In 1,400 years of suppression after the Islamic conquest, it has still preserved its original form and it has proven to have the most amazing vitality," he said, at an event this week in New York City, marking the release of the English edition of his book, "The 21: A Journey into the Land of Coptic Martyrs."

"The faith found in this church was and is stronger than all of the economic and social disadvantages Christians have to suffer. The Coptic Church has never been broken by political oppression. The Christianity of the first millennium is still to be found there and is … a living reality."

After immersing himself in the village culture surrounding these new saints, the Catholic author reached this conclusion: For these men, liturgy and martyrdom were "two sides of one and the same coin."

There was something truly iconic about those 21 men in orange jumpsuits kneeling on that beach, said Coptic Archbishop Angaelos of London. Thus, Coptic Orthodox leaders have declared Feb. 15 as a feast day honoring the 21 and all other modern Christian martyrs.

The unforgettable images showed the paradox of faith, he stressed.

After all, he said, stabbing the air with his hand, here were 21 "men who were -- for all intents and purposes -- weak and defeated, kneeling before their oppressors … with big knives to their throats. Yet suddenly it makes you think: Where is the power in this picture? Is it in the big men, with the big knives, with the covered faces, with the big voices, with the big threats, or is it in those who knelt bravely, with humility, confidence and resilience and a faithfulness that was unshaken and unshakable?"

Mosebach studied full versions of the ISIS video -- a message to the "nation of the cross" -- and focused on glances of encouragement the men exchanged before they were pushed face down into the sand and beheaded. These were "average" Copts, but church records detailed their visits to monasteries and six had been ordained as "minor clerics." Though most were illiterate, they chanted the three-hour liturgy by memory -- in Arabic, Greek and ancient Copt -- when priests visited them in Libya.

Family members, said Mosebach, took comfort from the brutal video because it recorded their loved ones saying, "Ya Rabbi Yassou! (Oh my Lord Jesus)" seconds before dying. These were the quick prayers of martyrs, adding them to the faithful referenced in Revelation, chapter 20: "I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast. … They lived and reigned with Christ a thousand years."

The faith found in Coptic villages survived waves of persecution, said Mossbach, reached by telephone. Now it faces shopping malls, smartphones and credit cards.

The modernized Christian culture of Europe, he said, seems to "be coming to an end. It gave mankind many blessings, in terms of art, music and culture. In our times, the tyranny of plastic is having a devastating impact on the Western church. …

"In a way, the brutal persecution of the Copts has helped keep them strong. They have retained a faith that still looks and functions like an ancient Christian church."