King Charles III said Canada is facing unprecedented challenges in a world that's never been more dangerous as he opened the Canadian Parliament on Tuesday with a speech widely viewed as a show of support in the face of annexation threats by U.S. President Donald Trump.

The king is the head of state in Canada, which is a member of the Commonwealth of former colonies. Trump’s repeated suggestion that Canada become the 51st state prompted Prime Minister Mark Carney to invite Charles to give a speech from the throne outlining the Liberal government's priorities for the new session of Parliament.

“We must face reality: since the Second World War, our world has never been more dangerous and unstable. Canada is facing challenges that, in our lifetimes, are unprecedented," Charles said in French, one of Canada's official languages.

He added that “many Canadians are feeling anxious and worried about the drastically changing world around them."

The king reaffirmed Canada’s sovereignty, saying the “True North is indeed strong and free."

Trump seemed to respond to the king's visit later Tuesday, writing that if Canada becomes the “cherished 51st State” it won't have to pay to join his future Golden Dome missile defense program.

“It will cost $61 Billion Dollars if they remain a separate, but unequal, Nation, but will cost ZERO DOLLARS if they become our cherished 51st State. They are considering the offer!,” Trump posted on social media.

A rare moment

It's rare for the monarch to deliver the speech from the throne in Canada. Charles’ mother, the late Queen Elizabeth II, did it twice. The king noted that it had been nearly 70 years since his mother first opened Parliament.

The visit to Canada was Charles' first as king and his 20th overall.

“Canada has dramatically changed: repatriating its constitution, achieving full independence and witnessing immense growth. Canada has embraced its British, French and Indigenous roots and become a bold, ambitious, innovative country that is bilingual, truly multicultural,” the monarch said.

The king said that among the priorities for the government is protection of the French language and Quebec culture, which are at the heart of Canadian identity.

He said when his mother opened a new session of Canadian Parliament in 1957, World War II remained a fresh, painful memory and the Cold War was intensifying.

"Freedom and democracy were under threat," he said. “Today, Canada faces another critical moment."

The speech isn't written by the king or his U.K. advisers, as Charles serves as a nonpartisan head of state. He read what was put before him by Canada’s government, but can make some remarks of his own.

Underscoring Canada's sovereignty

Canadians are largely indifferent to the monarchy, but Carney has been eager to show the differences between Canada and the United States.

After the United States gained independence from Britain, Canada remained a colony until 1867, and afterward continued as a constitutional monarchy with a British-style parliamentary system.

The king’s visit clearly underscores Canada’s sovereignty, Carney said.

Carney won the job of prime minister by promising to confront the increased aggression shown by Trump and made his first official trip to London and Paris, the capital cities of Canada's two founding nations.

Carney is eager to diversify trade, and the king said Canada can build new alliances. More than 75% of Canada's exports go to the U.S., and Trump has threatened sweeping tariffs on Canadian products.

Tense relationship with the U.S.

Just a few days ago the new U.S. ambassador to Canada, Pete Hoekstra, said that sending messages to the U.S. isn’t necessary. He said Canadians should move on from the 51st state talk, telling the Canadian Broadcasting Corp. that if there’s a message to be sent, there are easier ways — such as calling him or Trump.

“Move on. If the Canadians want to keep talking about it — that's their business. I'm not talking about it; Donald Trump is not talking about it," he said then.

The king said Canada must protect Quebec's dairy supply management industry, which Trump has attacked in trade talks.

And he said the Canadian government will protect the country's sovereignty by reinvesting in the Canadian Armed Forces. Trump has asserted that Canada doesn't spend enough on its military.

The king also said Canada would look to the European Union to purchase military equipment by joining the "REARM Europe” plan — a major defense procurement project to ramp up arms production in Europe.

The speech made no mention of buying from the U.S.

Pomp and ceremony

A horse-drawn carriage took Charles and Queen Camilla to the Senate of Canada Building for the speech. It was accompanied by 28 horses. After inspecting a 100-person honor guard and receiving a 21-gun salute, the king entered the building as the crowd cheered.

Former Canadian Prime Ministers Justin Trudeau and Stephen Harper were among those in attendance.

The king returned to the U.K. after the speech and a visit to Canada’s National War Memorial.

“Thank you for coming,” one voice called from the crowd as the royal couple moved toward their motorcade.

Justin Vovk, a Canadian royal historian, said the king’s visit reminded him of when Queen Elizabeth II opened the Parliament in Grenada, a member of the Commonwealth, in 1985. A U.S.-led force invaded the islands in October 1983 without consulting the British government following the killing of Grenada’s Marxist prime minister, Maurice Bishop.

Charles is also the king of the U.K., Australia, New Zealand, Jamaica and others — 14 realms in total. He exercises no political power in any of them.

King Charles III says Canada faces unprecedented dangers as Trump threatens annexation