Great leaders are often defined not by their beliefs, but by how they react when those beliefs are tested to the limit.
In the case of the Pakistani girl activist Malala Yousafzai, it's likely historians will focus on the horrific incident one year ago this week when she was shot in the head as she made her way home on the school bus.
In the eyes of the world, that was the defining moment in her fight for education - transforming her from an unknown schoolgirl to a global figurehead in the struggle for girls’ rights.
Yet the truly remarkable thing about Malala is how little that attack by the Taliban changed her.
Girls' education crusader
Malala was an outstanding young lady long before that day in October 2012.
Encouraged by her father, a headteacher and anti-Taliban campaigner, Malala began speaking out about girls' education aged just 11. That would be unusual in most societies, but especially in one where girls are often undervalued.
In 2008 she spoke at local press club meeting, telling the gathered journalists: "How dare the Taliban take away my basic right to education?"
Her words were remarkable, not only for their clarity and intelligence, but also for their fearlessness.
Just weeks earlier, the Taliban had taken control of the Swat Valley where Malala lived and issued an edict banning girls from attending school. Most people retreated in fear, but Malala thrust herself into the spotlight to protest against the injustice.
After the press club speech she made TV news appearances in both Pakistan and the United States. She also began writing an online diary for the BBC.
Clearly, Malala wanted to be heard. It's a tragedy that she had to be shot before the world truly listened.
The goal is peace, not a prize
The attack happened just two days before the first-ever International Day of the Girl (IDG) last October.
Today, on IDG 2013, it's clear that Malala has put girls at the centre of the debate about global development and justice.
The girl whose struggle was once ignored now has regular audiences with presidents, monarchs and Hollywood A-listers. She's been named one of the 10 most influential people in the world (higher even than Barack Obama) called "a symbol of hope, a daughter of the United Nations" by the UN secretary-general, Ban Ki-moon and just missed out on the Nobel Peace Prize at the announcement today.
The youngest ever Nobel Peace Prize winner, the journalist Tawakkol Karman, was 32 when she won it. Malala's nomination at just 16 is an incredible achievement.
Her profile has been transformed, but her focus and determination are the same as they ever were. "My goal is not to get a Nobel Peace Prize, it is to get peace," she told the BBC this week.
The Malala Fund
Progress towards that goal of peace has been rapid.
Malala's education petition received more than three million signatures, and a remarkable speech at the UN on her 16th birthday in July prompted Ban Ki-moon to recommit to Millennium Development Goal 2 - universal primary education - through the Global Education First Initiative. "One child, one teacher, one book and one pen can change the world," she told the UN.
Malala is now attending school in Birmingham, England. Her determination to ensure all girls get an education hasn't faltered even for a moment. Two weeks ago she launched the Malala Fund, which will support 40 Pakistani girls through school. "After a brutal attempt to silence her voice, it grew louder, and she more resolute," said actress and UN special envoy Angelina Jolie at the launch.
"She is powerful, but she is also a sweet, creative, loving little girl who wants to help others. Her goal is progress, not notoriety," added Jolie.
Support the Girl Declaration
Malala's journey from Pakistani school to the floor of the United Nations demonstrates the power of giving girls a voice. "Because of Malala there is a public understanding that something is wrong and has got to be done," said former UK prime minister Gordon Brown.
The global community now owes it to her to make sure no other girl has to endure such a horrific ordeal in order to be heard.
The Girl Declaration has been created to give girls like Malala all over the world a voice, and we are honoured that Malala herself has signed it.
Today the Declaration will be handed over to the UN. They need to read it, support it and use it to put girls at the heart of global development policy. It's the least that Malala - and the 250 million girls living in poverty - deserves.