Great and heroic leaders are typically made by their circumstances. A person can have a tremendous personality and all the skills needed to be a great leader and yet not be remembered as great because there was no real crisis to test them. Great leaders are those who arose in a time of crisis and did great things in that situation.
If we look at people we see as great leaders, we will see that this is true. We see Abraham Lincoln as a great leader because he was challenged by the Civil War. We see Franklin D. Roosevelt as a great leader because he was challenged by the Great Depression and by WWII. We see Martin Luther King, Jr. as a great leader because he was challenged by the need to gain civil rights for African Americans.
By contrast, let us imagine that Bill Clinton had all the qualities to be a great leader. Would he be seen as great by history? Probably not because there were no great crises that faced Clinton. Without great crises, there is no way for a leader to show his or her greatness
Great and heroic leaders, then, need to have great personalities. They need to have strength of character. They need to have political skills. But they also need to be confronted by a crisis that can bring out these characteristics in ways that will be obvious to the people.