The book that reshaped how English-language scholars understood the Christian communities of the Islamic Middle East carries a plain, declarative title: The Church in the Shadow of the Mosque. Its author, Sidney H. Griffith, a Catholic priest and professor at the Catholic University of America, died in Maryland in July 2026. He was 87 or 88, and for nearly five decades his work as a historian of Syriac and Arabic Christianity had made him one of the most cited scholars in his field.

Griffith was born in 1938 in Gaithersburg, Maryland, and attended local schools before enrolling at John Carroll High School in Washington, D.C., in 1952. He joined the Missionary Servants of the Most Holy Trinity, studied at the congregation's seminaries in Alabama and in Monroe, Virginia, and was ordained a Catholic priest in 1965, the same year he arrived at the Catholic University of America to begin an M.S. in Library Science, followed a year later by a Licentiate in Sacred Theology, according to Catholic University of America.

He stayed at the university to pursue the Semitic languages that would define his career, completing a Ph.D. in Semitic and Egyptian Languages and Literatures in 1978 with a dissertation on Syriac and medieval Arabic sources. He had already joined the faculty in 1977 and did not leave it again until retirement thirty-seven years later, in 2014, having been promoted to Ordinary Professor in 2001. He chaired the Department of Semitic and Egyptian Languages and Literatures for three terms, directed the university's Center for the Study of Early Christianity from 1984 to 1999, and served for decades as secretary of the Institute of Christian Oriental Research.

Between 1986 and 2008 he led three national scholarly societies in turn: the North American Patristics Society, the Byzantine Studies Conference, and the American Oriental Society. His research into how Christians in the medieval Islamic world defended and explained their faith in Arabic and Syriac fed directly into present-day dialogue. Griffith was a longtime member of the Eastern Orthodox-Roman Catholic Dialogue and took part in the Catholic-Muslim dialogue conducted under the U.S. Conference of Catholic Bishops, according to Georgetown University's Building Bridges Seminar. That work was recognized in 2009, when the Rumi Forum in Washington gave him its Rumi Peace Award for interfaith dialogue, the same year his 2008 book on Christians and Muslims in the world of Islam was counted among his university's award-winning scholarship.

Across his career Griffith published more than 130 articles and seven books, from close studies of the fourth-century Syriac poet Ephrem the Syrian to The Bible in Arabic: The Scriptures of the People of the Book in the Language of Islam in 2013. He held research fellowships at Dumbarton Oaks and at the Hebrew University of Jerusalem's Institute for Advanced Studies, and was a visiting professor at Georgetown University.

What Griffith leaves in the field is concrete rather than symbolic: seven books still assigned in graduate seminars on Eastern Christianity, more than 130 articles reconstructing how Christians wrote and argued in Arabic and Syriac under Muslim rule, and a generation of Catholic University students who learned to read those languages at his side. The institute and center he once directed, and the interfaith dialogues he carried into the U.S. bishops' conference, extended habits of careful, patient reading that he practiced for sixty-one years, from his ordination in 1965 to his death in 2026.