A nice little animation of the basics of what happened.
The “least you need to know” of this super important battle:
-It was the first major battle of the Civil War
-It was the first major battle on the Eastern seaboard in 80 years
-It was where Thomas Jonathan Jackson became, effective immediately and henceforth and forever, Stonewall (and we got this great song)
-It was a major eye opener for both sides about the determination of the other, but especially for the north. D.C. learned that the south could and would fight, and the CSA learned the same about the north, but unfortunately the southerners were far more energized by the “we licked the Yankees!” aspect than appalled by the hundreds of dead and thousands of wounded left on the battlefield.
-It was the bloodiest battle in U.S. history to that point, a record it wouldn’t keep for long.
-It’s most famous associated story (and a quite true one at that) is of the hundreds of spectators who came to watch like it was a football game; very very very very not good very bad idea as not only were many seriously injured when the Union troops were routed but they clogged the roads for the Union retreat
-It did not involve Lee or Grant- they didn’t become “Name Before the Credits” stars until the third season. (Sherman was a colonel at the battle- had a major psychological breakdown shortly after)
-It was the first battle in U.S. history, among the first in world history, in which trains played a major part (the whole reason Manassas was the CSA line was the railroad terminals)
-There were foul-ups, bleeps and blunders on both sides
-McDowell was the first of Lincoln’s commanders to drag his feet and pay for it, and this would become a major problem
-The first shell to find a target (actually 3 days before the battle) came into the dining room of Beauregard’s HQ which was in the house of sugar merchant Wilmer McLean. Nobody was hurt but it definitely startled McLean. If you’re not familiar with why this would be very ironic, watch the first minute or two of Ken Burns’ miniseries- I won’t ruin it for you.
There are lots of truly gory photographs and drawings (by people who were there) of the battle. The spectators were prepared for the sounds of cannons and drums but not for the carnage: not only had there not been a really pitched battle this far east in 80 years, but weaponry had come a very long way (much further than medicine). There are photographs of the piles of limbs that were cut off in field hospitals from this battle.