Napoleon, Empress Wu, Franklin D. Roosevelt, Oliver Cromwell, Akbar, Stalin. History provides many examples of strong leaders who left their marks, for better or for worse.
But what the past will not do is provide the magic formula for how to become an effective leader.
Effective leaders are able to manage both the day-to-day issues that press in on them and the bigger picture.
That is where a knowledge of history helps, as it shows patterns amidst all the noise of current events and reminds of possibilities other than those we are used to.