On this day 151 years ago, Confederate Gen. Robert E. Lee surrendered at the Battle of Appomattox Courthouse. In doing so, he unofficially ended the bloodiest conflict in American history: the Civil War.

The so-nicknamed War Between the States started in 1861 due disagreement over the role of the federal government in regulating which states could have slaveowners and which could not. By the end in 1865, more than 620,000 Americans had died, most from disease and most on the Union side, according to civilwar.org.

Leaders like President Abraham Lincoln and Lee spoke several times about the conflict both during and afterward. Here’s what they said about slavery, peace, fighting and war, collected from abrahamlincolnonline.org and sonofthesouth.net.

What Lincoln said:

“Let us then turn this government back into the channel in which the framers of the Constitution originally placed it.”

“Still, to use a coarse, but an expressive figure, broken eggs can not be mended. I have issued the Emancipation Proclamation, and I can not retract it.”

“Much is being said about peace; and no man desires peace more ardently than I. Still I am yet unprepared to give up the Union for a peace, which, so achieved, could not be of much duration.”

“I am naturally anti-slavery. If slavery is not wrong, nothing is wrong. I cannot remember when I did not so think and feel. And yet I have never understood that the presidency conferred upon me an unrestricted right to act officially upon this judgment and feeling.”

“And now, beware of rashness. Beware of rashness, but with energy and sleepless vigilance, go forward and give us victories.”

“War at the best, is terrible, and this war of ours, in its magnitude and in its duration, is one of the most terrible.”

What Lee said:

“I cannot consent to place in the control of others one who cannot control himself.”

“I have been up to see the Congress and they do not seem to be able to do anything except to eat peanuts and chew tobacco while my army is starving.”

“I would rather die a thousand deaths than surrender.”

“Northern politicians will not appreciate the determination and pluck of the South, and Southern politicians do not appreciate the numbers, resources and patient perseverance of the North. Both sides forget that we are all Americans. I foresee that our country will pass through a terrible ordeal, a necessary expiation, perhaps, for our national sins.”

“You have no idea what a horrible sight a field of battle is.”

“What a cruel thing is war: to separate and destroy families and friends, and mar the purest joys and happiness God has granted us in this world; to fill our hearts with hatred instead of love for our neighbors, and to devastate the fair face of this beautiful world.”