Thomas P. Melady, who served as United States ambassador to the Vatican under the presidency of George H. W. Bush, has died at his home in Washington at the age of 86.

Ambassador to the Holy See from 1989 to 1993, Dr. Melady was also a leading Catholic academic and intellectual, and an expert on sub-Saharan Africa. He passed away on Jan. 6 after suffering from brain cancer.

An authority on emerging independence movements in Africa, Dr. Melady served as U.S. ambassador to Burundi before becoming ambassador to Uganda in 1972, when the country was controlled by the dictator Idi Amin. He was recalled in 1973 when Amin criticized the Vietnam policies of President Richard Nixon.

His time spent in Rome was dramatic, when Soviet communism fell in large part due to the moral leadership of Blessed Pope John Paul II. Melady remarked that he worked very closely with the Holy See and the Pope in these transitions to democracy.

The American diplomat also took a leading role in opening talks that would result in the Vatican officially recognizing the state of Israel. This year marks the 20th anniversary of the Fundamental Agreement that officially opened diplomatic relations between the Holy See and Israel.

Born March 4, 1927, in Norwich, Conn. Thomas P. Melady served in the U.S. Army before graduating in 1950 from Duquesne University in Pittsburgh. He received a masters degree in 1952 and a doctorate in 1954, both in political science from Catholic University.

He also had academic appointments at Seton Hall University in New Jersey and other colleges before he was named ambassador to Burundi in 1969.

Dr. Melady was executive vice president of St. Josephs University in Philadelphia before serving as president of Sacred Heart in Fairfield, Conn., from 1976 to 1986.

After his time in Rome, he taught briefly at George Washington University and published a book about his diplomatic career. He was affiliated with the Washington-based Institute of World Politics, and was a member of the Cathedral of St. Matthew the Apostle in Washington.

He leaves behind his wife of 52 years, Margaret, two daughters, Christina and Monica, a brother, two sisters, and seven grandchildren.