(RNS) — John L. Allen Jr., a journalist who covered the Catholic Church for more than a quarter century, died of cancer in Rome on Thursday (Jan. 22), at age 61.

From the end of the 20th century until his death, Allen was essential reading for anyone who cared about the inner workings of the Vatican. He will be missed by all who treasured his expertise, his writing and his friendship.

“During the John Paul II and Benedict years, he was the go-to source for explaining what was happening in Rome,” said Austen Ivereigh, a Vatican commenter and the author of a biography of Pope Francis. “He was the great de-mystifier. He loved Rome for the extraordinary bird’e-eye view it gave of the church, and through it, the world. He used to say he had the best job in journalism.”

Catholics first benefited from Allen’s expertise when he was appointed the National Catholic Reporter‘s Vatican reporter in 2000. In 2014, The Boston Globe offered him the chance to launch Crux, a “vertical” — a news website within the Globe’s online paper.

When the economics of web publishing convinced the Globe to close the enterprise in 2016, Allen took Crux independent and ran it with funding from donors and advertising until his illness forced him to step back. As testimony to the success of the website, Crux’s senior Vatican correspondent, Allen’s wife, Elise Ann Allen, landed the first major interview with Pope Leo XIV in any publication.

In the meantime, Allen had published “Cardinal Ratzinger: The Vatican’s Enforcer of the Faith,” the first English-language biography of then-Cardinal Josef Ratzinger, Pope John Paul II’s doctrinal watchdog. Some felt the book was overly critical, and when Ratzinger was elected Pope Benedict XVI, in 2005, Allen acknowledged the criticism and gave a more favorable portrait of the man in “The Rise of Benedict XVI: The Inside Story of How the Pope Was Elected and Where He Will Take the Catholic Church.”

The same year, he put out a history of Opus Dei, the theologically conservative Catholic order of priests, and he published 11 books in all, most recently “Catholics and Contempt: How Catholic Media Fuel Today’s Fights, and What to Do About It,” reflecting his long-standing concern about divides among Catholics. 

After John Paul’s death in 2005, Allen was a constant presence on CNN, guiding viewers through the sometimes arcane process of electing a pope, a process the world had not witnessed for more than 25 years. He was a key voice for CNN again after Benedict resigned and the Catholic cardinals elected Pope Francis in 2013.

No matter where he was based, or in what format his reporting appeared, I, like many of my fellow Vatican observers and opiners, always checked to see what he said, because his columns, commentaries and books were sure to be filled with information and insightful analysis. For the most part, he stuck to reporting and left editorializing to others, although over dinner and wine he was often franker in his assessments.

Allen’s legacy will be felt far beyond the deep understanding of the Vatican he imparted during his lifetime. As editor of Crux, Allen hired and mentored some of the most prominent Vatican journalists of the next generation, including Inés San Martín; Christopher White, who went on to be NCR’s Vatican correspondent; and Religion News Service Vatican correspondent Claire Giangravé.

“John was a kind mentor, generous and gracious,” said Ivereigh. “He loved nothing more than fostering talent.”

Elise Allen is among a small group that owns Crux on Allen’s death and is expected to continue the publication’s work.