Queen Elizabeth II, the world’s longest-ruling monarch, ruled the U.K. for more than seven decades, and now the Commonwealth has its first king in generations. Former Prince Charles, the queen’s eldest child, will now be known as King Charles III.

A king is now on the throne at Buckingham Palace for the first time since 1952, when Elizabeth’s father, King George VI, died.

At the age of 73, Charles is the oldest monarch to take the throne in the lineage that dates back 1,000 years. His wife Camilla will be with him and will assume the title of Queen Consort, a position that carries no sovereign power.

In addition to ruling over the United Kingdom, King Charles III will also be the head of state for the 14 other members of the “Commonwealth realm,” Vox reported. Those realms include, Antigua and Barbuda, Australia, the Bahamas, Belize, Canada, Grenada, Jamaica, New Zealand, Papua New Guinea, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Solomon Islands and Tuvalu.

The king is also the head of the Commonwealth of Nations, which includes more than 50 countries that have ties — cultural or political — to the UK, including, Vox noted, as onetime parts of the former empire.

Though the British monarchy in recent years has been largely symbolic and apolitical, it does wield a kind of “soft power” that can influence the public. For example, as Prince Charles, the new king invested significant time and energy on the issue of climate change, including helping to lead the charge on the 2015 Paris Climate Accord. He has spent so much capital on the issue that he’s been branded the “Climate King” in many circles.

In the coming weeks and months, the world will see just how much he will leverage his influence amid growing global tensions, Brexit, a faltering economy and surging energy problems.