Today officially marked the end of Angela Merkel's time as Chancellor of Germany. She held the office for 16 years and transferred power to Olaf Scholz in Berlin on Wednesday.

US politician Hillary Clinton paid tribute on Merkel's last day and appeared to emphasize her world leadership during Donald Trump's four years in the White House.

Hillary Clinton takes shot at Trump in tribute to Merkel

On Twitter, Clinton thanked Merkel in a message accompanied by a photo of the pair sharing a laugh together. She wrote: "After a decade and a half in power, Angela Merkel passes on the chancellorship of Germany today.

"She led Europe through difficult times with steadiness and bravery, and for four long years, she was the leader of the free world. Thank you, Angela."

Presumably, Clinton's mention of a "four long years" references Trump's presidency, as "leader of the free world" is typically a term assigned to the president of the US. He was in office from 2016 to 2020 after defeating Clinton in the 2016 election.

But Trump was a notoriously difficult leader who at times withdrew the US from world agreements and made a spectacle out of global leadership summits.

Of course, one of the defining photographs of the Trump era features Merkel confronting the US president, who had crossed his arms in a stare down with the G7 leaders at the 2018 summit.

Famous Angela Merkel and Donald Trump photo from the G7 summit.

Trump, meanwhile, has been in the news lately as he's planning to launch his own social media service next year.

The 75-year-old, who could run for president again in 2024, also released a statement last week repeating his unproven claims of electoral fraud in the 2020 election. But he included an embarrassing typo in the combative statement, which went viral.