A simple plaque on the walkway at Independence Hall now commemorates that moment. It's a reminder of a bygone age when Philadelphia was part of a great crusade to save the Union.
In nearly every corner - from City Hall and Laurel Hill Cemetery to Memorial Hall and the Benjamin Franklin Parkway - statues, monuments, buildings, and artifacts speak of the city's role in what some have called the "second revolution."
The 150th anniversaries of events during that pivotal period will be marked in a series of programs, observances, exhibits - and even large battle reenactments in Fairmount Park - through 2015.
The effort will be launched at a fund-raising reception at 6 p.m. Monday at the National Constitution Center, which will host military reenactors, period music, and a preview of the film Civil War Philadelphia.
The city's history during the war "is a story that few people know about; we're not just a one-war town," said John Meko Jr., chair of the Civil War History Consortium of Greater Philadelphia, a nonprofit made up of dozens of Civil War- and history-related groups and institutions involved in the coming events.
Philadelphia "has been called one of the great battlefields of the Civil War - a battlefield of commerce, politics, and national finance," said Kim Sajet, vice chair of the consortium and president and chief executive officer of the Historical Society of Pennsylvania.
"It was also one of the great battlefields in the struggle for freedom and equality for African Americans."
The effort to share this history during the war's sesquicentennial will begin April 16 at the National Constitution Center, across from the spot visited by Lincoln as the incoming president, then revisited to lie in state after the assassination in 1865.