LONDON (AP) — At Windsor Castle, a majestic 50-meter-long (164-feet-long) mahogany table is being set. The royal grooms are busy polishing the horses’ hooves that will guide the regal carriages. Meanwhile, the military honor guard is rehearsing every precise step.

Inside and around the nearly 1,000-year-old castle located west of London, hundreds are preparing to help King Charles III orchestrate an impressive gathering as he welcomes U.S. President Donald Trump for an extraordinary second state visit this week.

The event, complete with glittering tiaras, resonant brass bands, and a lavish banquet served on 200-year-old silverware, showcases Britain’s unique flair for pomp and ceremony. However, this grand display serves a strategic purpose: to reinforce relations with one of the globe’s most influential leaders amidst the disruption caused by his America First agenda affecting longstanding trade and security ties.

“We’re buttering up to him,” said Robert Lacey, a royal historian and consultant on the Netflix series “The Crown.”

“He wouldn’t visit Britain if he didn’t get the opportunity to stay at Windsor Castle, likely to pay tribute to the (late) queen he holds in high regard, and to meet the king.”

Soft power in action

Though Britain’s monarchy ceded political authority three centuries ago to adopt a ceremonial status, the royals continue to be a significant tool of “soft power,” utilized by the government to reward allies and negotiate concessions from resistant partners.

State visits are the monarchy’s ultimate tool, with world leaders vying to get the full royal treatment.

During her seven decades on the throne, the late Queen Elizabeth II hosted a diverse array of leaders, from Romanian dictator Nicolae Ceauşescu to South African President Nelson Mandela.

The royals have also hosted the last four U.S. presidents, though not all were full-scale state visits.

Hospitality with purpose

While the impact of soft power is hard to quantify, it contributes to a feeling of friendship that “may incline another party to be more open to your entreaties,” said Martin Farr, an expert in modern British history at Newcastle University.

Six years ago, Britain sought Trump’s support as it prepared to leave the European Union. This time the U.K. is lobbying for favorable trade terms and help in combating Russian aggression in Ukraine.

“A new Trump presidency, a new prime minister, a different government, but the same sense of panic and the same feeling that the biggest lever we can pull with this president is to flatter him and to try and connect him with something he seems genuinely to be impressed by, which is monarchy, and the fact that his mother of course was born” in Scotland, Farr said.

So Prime Minister Keir Starmer hurried to Washington in February, just five weeks after Trump began his second term, and handed him the king’s invitation for a state visit.

It was the first time any world leader received the honor of a second state visit, and the first time the invitation was delivered in a personal letter from the king, which Trump proudly displayed for TV cameras.

“It’s a great, great honor, and that says at Windsor,” Trump said as he praised the king. “That’s really something.”

Pomp and circumstance

There will be plenty of glitz for a president who has gilded the Oval Office and plans to build a White House ballroom for 650 guests.

While the president and first lady Melania Trump will arrive in the U.K. late Tuesday, the meat of the visit begins the next day.

After welcoming the Trumps, Charles and Queen Camilla will accompany them on a carriage ride through the Windsor estate, then back to the castle along a path lined by members of the armed forces.

Inside the crenellated walls of the castle, which William the Conqueror started building in 1070, a military band will play the national anthems of both countries before Charles and Trump review the guard of honor in scarlet tunics and tall bearskin hats.

Hundreds of military personnel will take part in the ceremonies — mounted troops, foot guards and musicians — after months of rehearsals.

When rifles are shouldered, it will come with a single thwack. When boots hit the ground, they will do so in unison. “God Save the King” and “The Star-Spangled Banner” will be note-perfect.

Highlighting history

After the welcoming ceremonies, the Trumps will view an exhibit of documents and artwork put together to highlight the shared history of Britain and the U.S. The palace hasn’t said what will be included, but the options are myriad for two countries with common legal and democratic traditions that stretch back to Magna Carta, the historic charter of rights signed in 1215 at Runnymede, just a few miles from Windsor.

But the centerpiece of the visit will be Wednesday night’s state banquet, where the men will don white ties and tail coats and the women will wear designer gowns and jewels that will sparkle in the flickering light from antique candelabra.

“The tiaras will be out in force,’’ said Hugo Vickers, a royal historian and author of “Alice,” a biography of the late Prince Philip’s mother. “It will all look very splendid.”

Dinner for many

The king and queen will join their guests around the massive Waterloo Table, which is about half the length of a football field and has space for 160 guests. It takes five full days to set the table, which will be laid with the Grand Service, a silver-gilt dining service that includes more than 4,000 pieces ranging from serving dishes to dinner plates and egg cups.

Vickers said the silver and ceremonies pave the way for conciliation, which Elizabeth believed was the way to solve even intractable problems.

“Keir Starmer has, cleverly in a way, used the king to lure President Trump over here, to give him a very good time,” he said. “And (it’s) a wonderful opportunity, with all the goodwill that will be engaged at this point, to talk to him … and if there’s any hope of sorting out Ukraine, etc. This is all a step in the right direction.”

Those discussions take place Thursday, when Trump and Starmer meet at Chequers, the country estate of British prime ministers.