The Lincoln Assassination Conspiracy Trial:
A Chronology
March 4, 1865 Lincoln is inaugurated for his second term.  Some of the assassination conspirators, including Booth, are present in Washington for the inauguration.
March 15, 1865 Booth and other conspirators meet at Gautier's Restaurant at 252 Pennsylvania Avenue in Washington to plan the kidnapping of President Lincoln.  The plan calls for Lincoln to be taken to Richmond, where he would be held until exchanged for Confederate prisoners-of-war.
March 17, 1865 Booth's plan to kidnap Lincoln as he returns from a play at Campbell Hospital on the outskirts of Washington fails when Lincoln changes his plans.
April 6, 1865 John Surratt and Sarah Slater, a confederate agent, reach Montreal with a ciphered dispatch from Richmond--most likely one approving a plan to kill Lincoln by blowing up the Executive Mansion.
April 7, 1865 Richmond, capital of the the Confederacy, falls to Union troops.
April 8, 1865  Booth returns to Washington from New York, where he had met with his Confederate control, and told a friend "What a splendid chance I had to kill the President on the fourth of March [at the inauguration]."
April 9, 1865 At Appomattox, General Robert E. Lee surrenders the Army of Northern Virginia, effectively ending the Civil War.
April 10, 1865 The Union's capture of Thomas Harney, the Confederate explosives expert assigned the task of mining the Executive Mansion, dooms that Confederate plot. 
April 11, 1865 Lincoln speaks to a large crowd of ex-slaves and others celebrating the news of the Union victory.  Booth, listening to the speech with Louis Weichmann, resolves that it will be "the last speech" the President ever gives. 
April 13, 1865 Most houses and public buildings in Washington are illuminated by candles.  Papers describe the city as "all ablaze with glory."
April 14, 1865
(Good Friday)
Union troops reoccupy Fort Sumter, South Carolina, site of the Civil War's first conflict.

While attending a performance of Our American Cousin at the Ford's Theatre, Lincoln is assassinated in the presidential box by John Wilkes Booth.  Booth escapes by way of a back door.

Meanwhile, Lewis Powell (alias Lewis Payne), claiming to have medicine for Secretary of State William H. Seward, enters the Secretary's home.  Powell assaults the Secretary's son and tries to stab Secretary Seward in his bed.  Three people fight Powell off and he flees into the night.

Word of a Confederate conspiracy to assassinate government officials reaches Secretary of War Edwin Stanton as he waits anxiously near Lincoln's deathbed.

April 15, 1865 Lincoln dies at 7:22 in the morning.

Booth and Herold leave the farm of Dr. Samuel Mudd, where Booth had his broken leg treated and shaved off his mustache.

April 17, 1865 While soldiers question inhabitants of the home of Mary Surratt, a man carrying a pickax knocks on the door.  The man turns out to be Lewis Powell.  The man claims to be a hired laborer, but Mary Surratt denies hiring him and Powell---along with Surratt and her boarders--is arrested.

The same day, authorities tracking down the source of a letter from "Sam" found in Booth's hotel room, arrest Samuel Arnold.

Michael O'Laughlen, a boyhood friend of Booth, is also arrested.

April 19, 1865 Lincoln's funeral is conducted in the East Room of the White House.
April 20, 1865 George Atzerodt, who had taken a room in a hotel occupied by Vice Prsident Johnson on the 14th (and whose room was found to contain weapons and property of Booth), is captured in his bed.

Secretary of War Stanton offers a $100,000 reward for the capture of Booth, David Herold, and John Surratt.

April 24, 1865 Authorities arrest Dr. Samuel A. Mudd based on his contact with Booth (treating his broken leg after the assassination and allowing him to stay the night at his farm) and his unsatisfactory answers when questioned.
April 25, 1865 Secretary of War Edwin Stanton orders that the heads of the alleged conspirators be kept covered by canvas hoods.
April 26, 1865 John Wilkes Booth is shot and killed at Garrett's farm in Virginia.  A man found in Booth's company, David E. Herold, is arrested on suspicion of involvement in the conspiracy.
April 27, 1865 Alexander Gardner photographs alleged conspirators as they are imprisoned on the vessels Montauk and Saugus.  (Dr. Samuel Mudd and Mary Surratt, held at the Old Capitol Prison, are not photographed.)

Lewis Powell attempts to commit suicide by banging his head against a cell wall.  His canvas hood is replaced with a padded hood to thwart future similar suicide attempts.

May 1, 1865 President Andrew Johnson orders that the Lincoln assassination conspirators be tried by a military commission.
May 9, 1865 The Military Commission convenes for the first time.
May 10, 1865 The conspirators are arraigned before the Military Commission.  The Commission also adopts rules that will govern the trial.
May 12, 1865 Testimony begins in the Lincoln assassination conspiracy trial at the Old Arsenal Building in Washington.
June 1, 1865 The country observes a national day of mourning for Lincoln.
June 6, 1865 Major General John Hartranft, concluding that the prisoners are suffering too much from their hoods, orders them removed.
June 29, 1865 In secret session, the Commission begins its review of the trial evidence.
June 30, 1865 The Military Commission determines its verdicts and sentences.  Four conspirators (Herold, Mary Surratt, Powell, and Atzerodt) are sentenced to die, three (O'Laughlen, Arnold, and Mudd) to life terms, and one (Spangler) to a prison term of six years.
July 5, 1865 President Johnson approves the verdicts and sentences of the Military Commission.
July 6, 1865 Major General Hartranft tells four prisoners that they will be hanged the next day.  Lawyers for Mary Surratt prepare a petition for habeas corpus.
July 7, 1865 Judge Wylie of the Supreme Court of the the District of Columbia issues the writ of habeas corpus requested by Surratt's lawyers.  Attorney General Speed and President Johnson are informed of the writ's issuance.  The President signs an order: "I hereby declare that the writ of habeas corpus is suspended in cases such as this."

Shortly before 1:30 in the afternoon in the courtyard of the Old Arsenal Building, with George Atzerodt's last words, "May we meet in another world," the trap of the gallows is sprung and Atzerodt, Mary Surratt, Herold, and Powell are hanged.

August 11, 1865 Louis Weichmann signs an affidavit strongly implicating John Surratt, who fled the country, in the assassination conspiracy.
June 10-
August 11, 1867
John Surratt, after having been captured in Europe, is tried in a civilian court.  The jury is unable to reach a verdict in his case and in late August Surratt is released. 
September 23, 1867 Convicted conspirator Michael O'Laughlen dies in prison.
December 6, 1870 John Surratt begins a public lecture tour in which he provides his account of the assassination conspiracy. 
February 7, 1875 Four years after his release from prison, Edman Spangler dies.
June 10, 1883 Convicted conspirator Dr. Samuel A. Mudd dies.
September 21, 1906 The last of the convicted conspirators, Samuel Arnold, dies.
April 21, 1916 Suspected conspirator John Surratt dies.
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