Cardinal William Keeler, who helped ease tensions between Catholics and Jews and headed the oldest Roman Catholic diocese in the United States for 18 years, died Thursday. He was 86.

Archbishop William Lori said in a statement that Keeler died at St. Martin’s Home for the Aged in Catonsville, Maryland. No cause of death was released.

He retired in 2007 as the head of the archdiocese of Baltimore.

He devoted much of his clerical life to improving ties with other denominations, especially Jews. From 1992 to 1995, he was president of the National Conference of Catholic Bishops. He also served as moderator for Catholic/Jewish Relations and was a member of the Committee on Ecumenical and Interreligious Affairs.

In a 1993 interview with The Associated Press, Keeler said he developed his strong ecumenical bent while attending summer camp as a boy with Protestants and Jews.

Keeler was a priest for 37 years and served as an expert adviser to Pope John XXIII at the reforming Second Vatican Council of 1962-65.

He took over the Baltimore Archdiocese in 1989 after serving as bishop of Harrisburg, Pennsylvania. He was elevated to cardinal on Nov. 26, 1994.

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Keeler was born in San Antonio, Texas, and grew up in Lebanon, Pennsylvania. He was ordained on July 17, 1955.

As president of the National Conference of Catholic Bishops, Keeler kept conference business moving but also mediated potentially divisive issues, such as the role of women in the church and the celibacy of priests.

Several times, Keeler worked as a liaison to Jewish leaders. In 1987, he helped arrange meetings between the pope and American Jewish leaders, who felt stung by John Paul II’s earlier reception at the Vatican of former Austrian President Kurt Waldheim, alleged to have past Nazi links.

In 1993, Keeler met with Israeli Foreign Minister Shimon Peres to discuss issues including peace in the Middle East, improved Israeli-Vatican relations and efforts to combat anti-Semitism in Poland.

Perhaps the high point of his career was Oct. 8, 1995, when Pope John Paul II visited Baltimore. The pope led a Mass for 50,000 people at the Baltimore Orioles’ stadium.