The first president to be impeached by the House of Representatives was Andrew Johnson in 1868. Johnson, who became president following Abraham Lincoln's assassination, faced strong opposition from Congress due to his lenient Reconstruction policies toward the South after the Civil War. The House impeached him primarily for violating the Tenure of Office Act by attempting to remove Edwin Stanton from his post as Secretary of War without Senate approval. The impeachment trial took place in the Senate, where he narrowly avoided removal from office, serving the remainder of his term. Johnson's impeachment set a precedent for future political conflicts and the impeachment process.