Question

How did the first battle of bull run change the way people viewed the war?

Answer 1

Both sides figured going into First Bull Run (aka First Manassas) that all it would take was one big battle and the other side would surrender. Thus the war would be over in a day. It's been said that the Battle of Big Bethel just a few weeks earlier actually predicted the outcome of First Bull Run. There the Confederates also won the battle with a smaller force (though the difference between the two armies at Bull Run was 519 in favor of the North where as at Big Bethel it was 2,300 in favor of the North). Had Big Bethel beenas heavily publicized at the time as Bull Run later would be, maybe folks would have realized what Lee said long before Bull Run. On May 5, 1861 Lee had said: 

"They do not know what they say. If it comes to a conflict of arms, the war will last at least four years. northern politicians do 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 the country will have to pass through a terrible ordeal, a necessary expiation, perhaps, for our national sins." 

Prophetic? Perhaps so at a time when everyone and their brother believed it would be a single big battle and the war would be over. In the North they believed the Southerners would see the miltary might of the North and turn tail followed by a surrender of the Confederacy. And in the South they believed the Northerners would see they were willing to stand and fight so they would retreat and the North would then let the Confederacy go. But after Bull Run the relization began to dawn that the war wasn't going to be won in a day, that it was going to be a long hard fight.