In September 1862, Abraham Lincoln signed the first of two executive orders that would constitute the Emancipation Proclamation, a seminal event in American history on par in importance with the first shots of the American Revolution.

Less well-known — at least to non-D.C. denizens — was what Lincoln did about a half-year earlier: signing the District of Columbia Emancipation Act, authorizing the government to purchase the freedom of slaves in Washington, D.C. The event reverberated across the world and continues to have a special resonance for Washington-area natives.

“Before the Emancipation Proclamation, before Juneteenth, before the 13th Amendment, there was D.C. emancipation,” author and historian Carroll R. Gibbs said. “It represented to the international audience and the national audience the first federal strike against slavery, and in doing so it sent hope around the world to oppressed people.”

The city holds events each year to commemorate the April 16, 1862, signing. This year’s festivities include:

• From March 25 to May 14, the city will plant eight cherry blossom trees to commemorate the anniversary. This year’s Cherry Blossom Festival parade included a D.C. Emancipation Day float.

• Lectures include discussions of “Abraham Lincoln and the End of Slavery in the District of Columbia” by authors Robert Pohl and John Wennersten, 2:30 p.m. Sunday at the Historical Society of Washington and 11 a.m. April 24 at Rose Park.

• Until April 25, the National Archives will exhibit the original copy of the District of Columbia Emancipation Act. Beginning April 30, the Archives will host an exhibition on the Civil War that includes artifacts such as books and letters and interactive features including touch-screens.

• The African American Civil War Memorial Freedom Foundation and Museum will host a wreath-laying ceremony at the African American Civil War Memorial at 11 a.m. today. Frank Smith, director of the foundation and museum, estimated that about 200,000 African-Americans served in the Army during the Civil War and about 20,000 in the Navy.

“We believe virtually every African-American family had some ancestor engaged in one of these regiments,” Smith said.

• On Friday, DC Vote will bring together members of the DC Voting Rights Coalition, an umbrella organization whose members seek Congressional representation for the District, for an 8 a.m. rally in front of the Capitol followed by meetings at more than 130 Congressional offices. “We want to remind Congress and the American people that Washington, D.C., residents are not fully emancipated,” DC Vote Executive Director Ilir Zherka said. “Our view is that D.C. residents are still second-class citizens.”