The Rev. John H.P. Reumann, 81, formerly of Mount Airy, professor emeritus at the Lutheran Theological Seminary in Philadelphia who was a force in Lutheran-Roman Catholic dialogues, died of prostate cancer Friday at The Hill at Whitemarsh, a retirement community in Lafayette Hill.

Dr. Reumann was invited to become an instructor at the seminary in 1950, the year he graduated and was ordained a Lutheran minister. While on the faculty, he earned a master's degree in sacred theology from the seminary, and a master's degree in the classics and a doctorate in the classics and Semitic studies from the University of Pennsylvania. After retiring in 1996, he continued to teach an occasional class until last year. As a professor, "he was always self-assured, but never aloof," said the Rev. Ellen Anderson, a former student who is now a seminary administrator.

Dr. Reumann was the author of 15 books, edited or contributed to dozens of books and articles and was former editor of the Journal of Biblical Literature. In April, he completed the final proofing for a commentary on the New Testament book of Philippians to be published by Yale University Press.

Besides his scholarly pursuits, Dr. Reumann was "an excellent citizen of the church and served tirelessly on the local synodical and national levels, " said Dr. LeRoy Aden, a former seminary colleague.

For more than 30 years Dr. Reumann was the linchpin of the Lutheran-Roman Catholic dialogues, which culminated in the Joint Declaration on the Doctrine of Justification, Aden said. In the declaration, both churches agreed that salvation is achieved by grace alone, in faith in Christ's saving work, and not because of any merit on our part.

"He was a careful and meticulous scholar," said the Rev. Joseph Fitzmyers, professor emeritus at Catholic University of America, who worked on the declaration with Dr. Reumann. The two men were in Augsburg, Germany, when the declaration was signed by the Vatican and the Lutheran World Federation in 1999.

In the 1980s, Dr. Reumann served on the committee that led to the formation of the Evangelical Lutheran Church in America.

A graduate of Lansdale High School, Dr. Reumann earned a bachelor's degree from Muhlenberg College and later served on the college board. In 1958 he married Martha Brobst; both their fathers were Lutheran ministers.

He was an avid Phillies fan, stamp collector and traveler. While at the seminary he enjoyed sabbaticals to Cambridge and Oxford, England, Germany, India and Israel.

In addition to his wife, Dr. Reumann and is survived by daughters Rebecca Reumann-Moore, Miriam Sadler, and Amy; and four grandchildren.

The funeral will be at 2 p.m. tomorrow at Trinity Evangelical Lutheran Church, 1000 W. Main St., Lansdale, where Dr. Reumann's late father, Paul, had been pastor for 33 years.

Contact staff writer Sally A. Downey at 215-854-2913 or sdowney@phillynews.com.