In Brief
Five thousand seven hundred and sixty years ago the world experienced the very first Rosh Hashanah. According to Rabbi Eliezer, it was on this day that Adam was created. God's creation was complete.
Our sages tell us that on this very day, Adam violated the commandment that God gave him - the prohibition to eat from the tree of life. On this day God said to Adam "As you were judged before me this day and emerged forgiven, so will your children be judged before me on this day and emerge forgiven". Thus, from the beginning of our history, Rosh Hashanah has been marked with judgement and forgiveness.
On Rosh Hashanah we celebrate the creation of the world, we mark the Kingship of God, and we stand in judgement as His humble servants.