If Harriet Beecher Stowe was the woman whose book, "Uncle Tom's Cabin," caused the Civil War, the Rev. Albert Barnes probably was the preacher most responsible for American Presbyterians' "Thirty Years War."

In the early 1830s, the Philadelphia minister argued against original sin and for unlimited atonement. Unlimited atonement is the belief that Jesus died for the sins of all people, while more traditional Presbyterians believed he died only for those predestined to accept him as savior.

In 1837, shortly after the Rev. Barnes faced, but was acquitted, of heresy charges, Presbyterians split into Old School and New School divisions.

The New School, in general, favored a "modern" interpretation of Scripture, while the Old School backed what it believed to be the views of John Calvin, the denomination's 16th century founder.

Over the decades, however, the two sides recognized that more united than divided them. The schism ended in Pittsburgh in 1869 with what The Daily Post called "The Marriage of the Assemblies."

"The procession numbered about seven hundred gentlemen, and, without wishing to step aside to compliment or flatter those in the ranks, we must record what was the universal remark, that a finer or more dignified body of citizens was never observed together in this city," the Pittsburgh Gazette reported on Nov. 13, 1869.

The general assemblies of the two groups had been meeting separately in Pittsburgh for the previous two days -- the New School at the Third Presbyterian Church and the Old School in the First Presbyterian building. Both groups heard from and approved a report from a Joint Committee of Union.

"All that remains to be done," the Gazette reported on Nov. 12, "is the formal announcement ... of the Basis of Union ... and the dissolution of the separate Assemblies, which will take place at ten o'clock today, to be followed immediately by the 'flowing together' of the members in public meeting in the Third Church."

That 'flowing together' was choreographed as carefully as a military review.

Delegates from each assembly were instructed to leave their churches that morning and form single lines along both sides of Fifth Avenue. "The two lines being now opposite each other, the two Moderators will pass to the centre of the street, join arms and proceed up Fifth avenue, followed by the procession, which will be formed by the two lines joining in the center of the street so that an Old School and New School Commissioner will join, and, walking arm in arm the line will pass up Fifth avenue," the Gazette explained on the morning of the event.

The ceremonies appear to have gone off as their planners hoped. "As this important and imposing body quietly and unostentatiously moved through our streets there were none who looked idly on, but all felt deeply impressed with the solemnity of the occasion and the grandeur of the deed of reunion among so numerous a branch of the Christian family about to be ratified," the Gazette reported the day after the events.

Coverage of the assemblies and the combined closing exercises drew gavel-to-gavel coverage in both The Daily Post and The Pittsburgh Gazette. On Nov. 13, The Post also gave its readers no-holds-barred "Verbographic sketches" of some of the major players.

Ezra A. Huntington, D.D., was 56 in 1869, when 50 was the present century's 70. "Professor Huntington, who has passed the rubicon of life ... shows the footprints of the years that evidently have not fallen lightly upon him," an anonymous reporter wrote.

New Church Home Mission Secretary Edmund Francis Hatfield "cannot be regarded as a pleasing speaker, his words being rather constrained, though distinct."

New Jersey pastor Charles K. Imbrie was of "medium height and wiry build and frame [and] he is as mercurial and nervous as a Frenchman." The Rev. Mr. Imbrie had a high forehead, "with his head almost destitute of capillary covering." Lack of "capillary covering" was a 19th century euphemism for baldness.

The Gazette on Nov. 13 called the event "one of the most important ecclesiastical councils ever held in this country." The newly reunited Presbyterian church brought together 2,381 ministers and 258,903 congregation members from the "Old School" and 1,848 ministers and 192,264 members from the "New School," according to contemporary general assembly minutes located by librarian Anita Johnson at Pittsburgh Theological Seminary.