Monday is Confederate Memorial Day in Alabama, one of three states that still set aside a state holiday — meaning government offices are closed — to honor those who fought for the Confederacy during the American Civil War. The others are Mississippi, which will celebrate Confederate Memorial Day on April 30; and South Carolina, which celebrates on May 10.

In addition, other states, such as Florida (which will celebrate Confederate Memorial Day on Thursday) and Texas (which celebrated Confederate Heroes Day on January 19), honor the legacy of the Confederacy without closing government offices.

And in several states — including Alabama — Confederate figures like President Jefferson Davis and Gen. Robert E. Lee are also honored with their own holidays, with supporters arguing that doing so is important to preserve Southern history.

Now, 157 years after the first shots were fired at Fort Sumter — marking the beginning of the Civil War — Americans still debate its causes. But the underlying reasoning for the secession of Southern states from the Union, and the launching point for the bloodiest conflict in American history, couldn’t be more clear. In fact, the instigators themselves explained them.

The Confederacy was built on slavery and created to save slavery

The Confederacy, or the Confederate States of America, was established with the purpose of preserving the institution of slavery. This is now viewed as a controversial take in 2018, but it is, in fact, true. Alabama seceded from the Union on January 11, 1861, in the belief, as stated during the Alabama Secession Convention held that month, that “the institution of African slavery now existing in the slaveholding states” was “a moral, social, and political blessing.”

A few weeks earlier, in December 1860, Stephen F. Hale, Alabama’s commissioner to the state of Kentucky, wrote the following to Kentucky Gov. Beriah Magoffin regarding Alabama’s reasonings for exiting the Union (emphasis added):

What Southern man, be he slave-holder or non-slave-holder, can without indignation and horror contemplate the triumph of negro equality, and see his own sons and daughters in the not distant future associating with free negroes upon terms of political and social equality, and the white man stripped by the heaven-daring hand of fanaticism of that title to superiority over the black race which God himself has bestowed? In the Northern States, where free negroes are so few as to form no appreciable part of the community, in spite of all the legislation for their protection, they still remain a degraded caste, excluded by the ban of society from social association with all but the lowest and most degraded of the white race. but in the South, where in many places the African race largely predominates, and as a consequence the two races would be continually pressing together, amalgamation or the extermination of the one or the other would be inevitable. Can Southern men submit to such degradation and ruin? God forbid that they should.

He added:

If we triumph, vindicate our rights, and maintain our institutions, a bright and joyous future lies before us. We can clothe the world with our staple, give wings to her commerce, and supply with bread the starving operative in other lands, and at the same time preserve an institution that has done more to civilize and Christianize the heathen than all human agencies besides-an institution alike beneficial to both races, ameliorating the moral, physical, and intellectual condition of the one and giving wealth and happiness to the other.

(The “institution” to which he was referring was the institution of slavery.)

In 1860, 45 percent of people in Alabama were slaves.

Mississippi seceded from the Union on January 9, 1861. As written in its articles of secession (“A Declaration of the Immediate Causes which Induce and Justify the Secession of the State of Mississippi from the Federal Union”):

Our position is thoroughly identified with the institution of slavery — the greatest material interest of the world. Its labor supplies the product which constitutes by far the largest and most important portions of commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature, none but the black race can bear exposure to the tropical sun. These products have become necessities of the world, and a blow at slavery is a blow at commerce and civilization. That blow has been long aimed at the institution, and was at the point of reaching its consummation. There was no choice left us but submission to the mandates of abolition, or a dissolution of the Union, whose principles had been subverted to work out our ruin.

Among the reasons for the state to exit the United States were the following:

[The United States] advocates negro equality, socially and politically, and promotes insurrection and incendiarism in our midst. [The United States] has enlisted its press, its pulpit and its schools against us, until the whole popular mind of the North is excited and inflamed with prejudice. [The United States] has made combinations and formed associations to carry out its schemes of emancipation in the States and wherever else slavery exists.

In the Census of 1860, roughly 55 percent of people in Mississippi were slaves, and 49 percent of white Mississippians owned slaves.

We are still relitigating the Civil War

Last summer, white nationalists rallied in Charlottesville, Virginia, purportedly to stop Charlottesville’s government from taking down a statue of Confederate Gen. Robert E. Lee. But that statue wasn’t put in place in the aftermath of the Civil War — it was dedicated in 1924, 59 years after the war ended.

And many of the holidays honoring Confederate soldiers were similarly delayed — in Florida, Confederate Memorial Day was first celebrated in 1895, years after the end of the Civil War but coinciding exactly with the height of Jim Crow racism. These holidays and memorials weren’t intended to honor the dead; they were meant to terrify the living — especially black Americans, already subjected to rampant discrimination and violence across the South (and throughout the North too).

As my colleague Libby Nelson wrote in 2015:

The Confederacy itself was founded to preserve slavery and promote white supremacy (see, for example ... the speech from the Confederacy’s vice president that declared the Confederacy’s cornerstone “rests upon the great truth that the Negro is not equal to the white man; that slavery — subordination to the superior race — is his natural and normal condition”).

Corrected to show that Confederate Memorial Day is a state holiday in South Carolina.