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History of Congress and the Capitol

This is the story of one of the world's great experiments in government by the people.

For more than two centuries, a new Congress has convened every two years following elections that determine all the seats in the House and one-third of those in the Senate. While the individuals change, the institution has endured-through civil and world wars, waves of immigration and great migrations, and continuous social and technological change.

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Unprecedented growth in the 1850s strained the fragile agreements that had kept the nation united, but had also kept it part slave, part free. The addition of each new state to the Union rattled the delicate political balance carved out by compromises in Congress. In 1854, the Kansas-Nebraska Act allowed residents of each of these new territories, rather than Congress, to decide whether to permit slavery. While intending to keep the nation together, this act inflamed sectional tensions, producing open warfare between pro- and antislavery forces in Kansas, and led directly to the Civil War.

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Images of the Era - 1851-1877

While the Civil War raged, a great cast-iron dome was added to the Capitol, symbol of an enduring nation.

While the Civil War raged, a great cast-iron dome was added to the Capitol, symbol of an enduring nation.

Architect of the Capitol

South Carolina seceded from the Union in December 1860, followed by 10 other Southern states.

South Carolina seceded from the Union in December 1860, followed by 10 other Southern states.

Prints and Photographs Division, Library of Congress

Confederates burned Richmond, Virginia, their capital, before it fell to Union forces in April 1865.

Confederates burned Richmond, Virginia, their capital, before it fell to Union forces in April 1865.

Prints and Photographs Division, Library of Congress

President Lincoln’s Emancipation Proclamation of January 1, 1863, freed all slaves in Confederate-controlled territory.

President Lincoln’s Emancipation Proclamation of January 1, 1863, freed all slaves in Confederate-controlled territory.

Prints and Photographs Division, Library of Congress

At Gettysburg, in 1863, the bloodiest battle of the Civil War ended the Confederate army’s northward advance.

At Gettysburg, in 1863, the bloodiest battle of the Civil War ended the Confederate army’s northward advance.

Prints and Photographs Division, Library of Congress

John Wilkes Booth, a Confederate sympathizer, assassinated President Lincoln at Ford’s Theater, April 14, 1865.

John Wilkes Booth, a Confederate sympathizer, assassinated President Lincoln at Ford’s Theater, April 14, 1865.

Prints and Photographs Division, Library of Congress

The nation celebrated its 100th anniversary with a grand exhibition in Philadelphia, 1876.

The nation celebrated its 100th anniversary with a grand exhibition in Philadelphia, 1876.

Prints and Photographs Division, Library of Congress

Japan’s first emissaries to the United States exchanged treaty ratification papers and visited Congress in 1860.

Japan’s first emissaries to the United States exchanged treaty ratification papers and visited Congress in 1860.

Alexander Gardner and Mathew B. Brady, The Japanese Ambassadors, First Japanese Mission to the United States, ca. 1860, salt print, 15 x 16 3/16 in., The J. Paul Getty Museum, Los Angeles

Soldiers of the 4th U.S. Colored Infantry defended Washington, D.C. After January 1863, African-American soldiers made up almost ten percent of the Union Army.

Soldiers of the 4th U.S. Colored Infantry defended Washington, D.C. After January 1863, African-American soldiers made up almost ten percent of the Union Army.

Prints and Photographs Division, Library of Congress

After the Civil War, African-American men gained political influence when the Fifteenth Amendment ensured their voting rights.

Prints and Photographs Division, Library of Congress

The Freedmen’s Bureau, established in 1865, provided assistance and education to former slaves.

The Freedmen’s Bureau, established in 1865, provided assistance and education to former slaves.

William Gladstone Collection

Congress founded Howard University, one of several new colleges for African-Americans, in 1867.

Congress founded Howard University, one of several new colleges for African-Americans, in 1867.

Moorland-Spingarn Research Center, Howard University

The 1862 Pacific Railroad Act spurred the Union Pacific to complete a transcontinental rail link.

The 1862 Pacific Railroad Act spurred the Union Pacific to complete a transcontinental rail link.

The Andrew J. Russell Collection, the Oakland Museum of California

Chinese immigrants provided much of the labor for construction of the transcontinental railroad.

Chinese immigrants provided much of the labor for construction of the transcontinental railroad.

Prints and Photographs Division, Library of Congress

On the tree-sparse grasslands of the Great Plains, many homesteaders built houses of sod.

On the tree-sparse grasslands of the Great Plains, many homesteaders built houses of sod.

Nebraska State Historical Society, RG2608 PH 0 1249, copy and reuse restrictions apply

Sitting Bull’s Sioux and Cheyenne warriors won a battle against the U.S. Army at Rosebud River, Montana, 1876.

Sitting Bull’s Sioux and Cheyenne warriors won a battle against the U.S. Army at Rosebud River, Montana, 1876.

Prints and Photographs Division, Library of Congress

Government schools in the late 1800s aimed to integrate Native Americans by forcing them to adopt European dress and speak English.

Government schools in the late 1800s aimed to integrate Native Americans by forcing them to adopt European dress and speak English.

Cumberland County Historical Society, Carlisle, PA

Designing a New Dome

The Capitol developed into its current majestic form through enlargements and a new dome that were designed by Thomas U. Walter of Philadelphia. When he came to Washington in 1851, Walter was already one of the nation’s leading architects. He had designed Girard College in Philadelphia, private mansions and villas, churches, commercial buildings, and engineering projects located up and down the east coast and as far away as Venezuela. It was, however, his work for the federal government—especially the Capitol’s great iron dome—that placed him at the pinnacle of the architectural profession and secured his enduring place in American history.