In 18 years at the helm of her party, Angela Merkel has undergone a transformation, becoming the champion of closer European integration and the liberal international order.
When she became the head of the Christian Democratic Union of Germany (CDU) in 2000, she was the first female leader of her party. Formerly a cabinet minister, Mrs Merkel soon grew into her role.
Today, in her fourth term as chancellor, she is often referred to as mutti (mummy) Merkel, known for her staunch defence of the liberal international order, freedom of movement and her steady hand in a crisis.
By the time she leaves the office of chancellor in 2021, she will have served 20 years as a leader in Germany.
Here are the moments that made Mrs Merkel the de facto leader of the free world she is today:
2005: Germany's first female chancellor
Five years after being elected leader of her party, a coalition between the CDU and its sister party the CSU narrowly won a simple majority in parliamentary elections.
Mrs Merkel was sworn in as chancellor and immediately got to work fixing a lagging economy.
2011: "If the euro falls, then Europe falls"
In the throes of the 2008 financial crisis, Mrs Merkel was a leader in negotiating the strategy for Europe's effort for self-preservation.
When Greek banks could not afford to service their debt, it was Mrs Merkel who held the most power. German banks held the largest amount of Greek debt, putting livelihoods in her hands.
2013: Private calls made public
Shortly after securing her third term as chancellor, WikiLeaks revealed the US's NSA had tapped the phones of world leaders, prompting Mrs Merkel to issue a rebuke.
"Spying between friends, that's just not done," she said.
2015: On refugees: “Wir schaffen das”
"We can do it," was the phrase Mrs Merkel repeated again and again throughout the summer of 2015. In the midst of a refugee crisis taking over Europe, she opened up Germany's doors to migrants crossing the Mediterranean.
The bold move set herself apart from other leaders who decided to close their borders and erect walls.
Scolding right-wing Hungarian Prime Minister Victor Orban for putting a fence across his border, Mrs Merkel said: “I lived behind a fence long enough," referring to her time growing up in East Germany. "It is not something I wish to do again.”
2017: Taking the reigns as leader of the free world
When US President Donald Trump declared his policy of America First, the de facto reins of leader of the free world – banging the drum for globalisation, multilateralism and co-operation – passed on to Mrs Merke, although she shied away from the label.
Towards the end of his term as president, Barack Obama expressed his guilt at leaving "Angela alone" in Europe, which was experiencing a rising tide of populism.
With Mrs Merkel not seeking election in 2021, party members have three years to find her successor.