BERLIN — Angela Merkel has been chancellor of Germany and unofficial leader of Europe for 13 years.

When she was first appointed, George W. Bush was still in the White House and Tony Blair ran Britain. There was no Twitter and no iPhone. Liberal democracy was in seemingly inexorable expansion mode, with the Orange Revolution having recently swept through Ukraine. Mariah Carey had topped the charts for months with “We Belong Together.”

On Friday, Ms. Merkel’s conservative party chose her successor as party leader, marking the beginning of the end of her long political life. She is on her third American president, her fourth French president and her seventh Italian prime minister. Democracy seems increasingly under threat. “Solo,” by Clean Bandit, is playing on the radio.

[Who will replace Angela Merkel as the conservatives’ leader, and what will it mean for her party?]

Over the years, Ms. Merkel has put President Vladimir V. Putin of Russia in his place (even when he tried to intimidate her with his dog). She bonded with President Barack Obama and stood up to President Trump. She became an icon of hope for refugees and an object of scorn for populists. As Europe’s most powerful leader, she became an inspiration to women in a world dominated by men.