Two armies amassed in Fairfax Virginia. Each was sure this would be the day for one decisive battle to bring an end to their differences. History notes that within a few hours the army from the north was routed and the army from the south was too disorganized to pursue.
Nearly 5000 men were killed wounded or captured that day on both sides. The hopes of a quick end to hostilities were dashed and so began the beginning of one of the bloodiest conflicts ever on this planet.
Thus-The Battle of Bull Run, (or Manassas if you are from the South). The first great infantry battle of Americas Civil War.