By looking at some of the best leaders today and throughout history, it is possible to identify traits and characteristics that collectively define them. Although no one – including leaders – is perfect, there are certain behaviors and qualities that all exemplary leaders exhibit. Here is a list of three important truths about leadership.

1. Leaders are Honest and Humble

Even though the proverbial story about George Washington and the cherry tree is a myth, this American Founding Father and president is still a beacon of honesty and humility in leadership. He set the precedent for later American presidents by being honest about his military commission and retiring after the Revolutionary War. This unconventional action established the principle of ordered liberty in America, which has held the country to its constitutional roots ever since. Ultimately, honesty and humility help leaders to think less about themselves and more about those they serve.

2. Leaders Practice Optimism

Kathy Giusti, founder and CEO of the Multiple Myeloma Research Foundation, is a shining example of optimism. Diagnosed with myeloma in 1996, Giusti has made the best of her setback by revolutionizing conventional research of this cancer type. She has been praised for her ability to think outside the box and find solutions for problems that seem insurmountable. Leaders of today can learn from her example by looking for positivity in the face of difficulty. Pessimism may seem practical, but optimism is healthful – and never wasted.

3. Leaders are Patient and Persistent

From the age of 25, Nelson Mandela fought for equality and justice in South Africa. Even while he was in prison – a state that lasted 27 years – he remained persistent in his activism, even organizing a movement of civil disobedience at Robben Island Prison that resulted in dramatically improved living conditions for the inmates. Mandela’s patient persistence helped him to end the Apartheid, after which he became President of South Africa in 1994. Successful leaders operate through patience and persistence to achieve their goals.

The examples set by leaders such as George Washington, Kathy Giusti, Nelson Mandela and many others are united by these three truths. Honesty, humility, optimism, patience and persistence are all necessary qualities for world-changing leadership.