John Brown's capture of the Federal Arsenal at Harper's Ferry.
Many significant events occurred in 1865,possibly the MOST significant being the surrender of Gen. Robert E Lee's Army of Northern Virginia in April 1865.
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Take your pick from the related link.
the civil was
The American Civil War.
The event that occurred after the voters in Texas approved the states new constitution was the civil war.
The probability based on an event that has already occurred is 100%. If the event has occurred, it has occurred.
what was the supreme court case that started the civil war
Several Civil War Battles including Bull Run, Chancellorsville and the battle of Appomattox Courthouse.
ending slavery through the civil war? im not sure
The Warsaw Ghetto Uprising. See related question below.
The Vietnam War is the event that occurred in the Tonkin Gulf.