AMMAN, Jordan — Jordan’s crown prince married the scion of a prominent Saudi family on Thursday in a palace ceremony attended by royals and other VIPs from around the world, as massive crowds gathered across the kingdom to celebrate the region’s newest power couple.

The marriage of Crown Prince Hussein, 28, and Saudi architect Rajwa Alseif, 29, drew a star-studded guest list including Britain’s Prince William and his wife Kate, as well as U.S. First Lady Jill Biden.

The celebrations hold deep significance for the region, emphasizing continuity in an Arab state prized for its longstanding stability and refreshing the monarchy’s image after a palace feud. It even could help resource-poor Jordan forge a strategic bond with its oil-rich neighbor, Saudi Arabia.

The bride, wearing an elegant white dress by Lebanese designer Elie Saab, arrived at Zahran Palace in a 1968 Rolls-Royce Phantom V custom-made for the crown prince’s late great grandmother. The crown prince arrived earlier in full ceremonial military uniform with a gold-hilted saber.

The families and their guests gathered in an open-air gazebo decked with flowers and surrounded by landscaped gardens for a traditional Muslim wedding ceremony known as “katb al-ketab.” The crowd erupted in applause after the signing of the marriage contract. Alseif will henceforth be known as Her Royal Highness Princess Rajwa Al Hussein, according to a royal decree.

Several miles away, a jolt went through a packed ancient Roman amphitheater as viewers watched the couple seal their vows and exchange rings on a wide screen. After several minutes of stillness, the crowd of some 18,000 people were on their feet, waving flags and shrieking with excitement at one of several viewing parties held across the nation.

Samara Aqrabawi, a 55-year-old mother watching the livestream with her young daughter, said the ceremony was more impressive than she imagined. “I wish for all mothers and fathers in Jordan and in the world to feel like they’re surely feeling,” she said of the king and queen.

The newlyweds later emerged from the palace in a white custom Range Rover escorted by several bright red Land Rovers, motorcycles and a military marching band — a nod to the traditional horse-mounted processions during the reign of the country’s founder, King Abdullah I.

The kingdom declared Thursday a public holiday so crowds of people could gather to wave at the couple’s motorcade amid a heavy security presence across the city. Tens of thousands of well-wishers attended free concerts and cultural events.

On Thursday morning, Saudi wedding guests and tourists — the men wearing white dishdasha robes and the women in brightly colored abayas — filtered through the marbled lobby of the Four Seasons Hotel in Amman. Noura Al Sudairi, an aunt of the bride, was wearing sweatpants and sneakers on her way to breakfast.

“We are all so excited, so happy about this union,” she said. “Of course it’s a beautiful thing for our families, and for the relationship between Jordan and Saudi Arabia.”

Excitement over the nuptials — Jordan’s biggest royal event in decades — has been building in the capital of Amman, where congratulatory banners of Hussein and his beaming bride adorn buses and hang over winding hillside streets. Shops had competing displays of royal regalia.

“She looks like such a princess that I think she deserves him,” Suhair Afaneh, a 37-year-old businesswoman, said of the bride, lingering in front of a portrait of Hussein in a dark suit. “But so what, I’ll still be in love with him.”

She contemplated buying Hussein’s portrait to hang in her bedroom but her nieces persuaded her that her husband might not approve.

Jordan’s 11 million residents have watched the young crown prince rise in prominence in recent years, as he increasingly joined his father, Abdullah, in public appearances. Hussein has graduated from Georgetown University, joined the military and gained some global recognition speaking at the U.N. General Assembly. His wedding, experts say, marks his next crucial rite of passage.

“It’s not just a marriage, it’s the presentation of the future king of Jordan,” said political analyst Amer Sabaileh. “The issue of the crown prince has been closed.”

The wedding may create a brief feel-good moment for Jordanians during tough economic times, including persistent youth unemployment and an ailing economy.

Palace officials have turned the event — a week after Jordan’s 77th birthday — into something of a PR campaign. Combining tradition and modernity, the royal family introduced a wedding hashtag (#Celebrating Al Hussein) and omnipresent logo that fuses the couple’s initials into the Arabic words “We rejoice.”

Zahran Palace in Amman, where the marriage ceremony was held, hasn’t seen such pomp and circumstance since 1993, when, on a similarly sunny June day, Abdullah married Rania, who was born in Kuwait to Palestinian parents. Decades earlier, Abdullah’s father, the late King Hussein, sealed his vows in the same garden with his second wife, the British citizen Antoinette Gardiner.

In addition to the Prince and Princess of Wales, the guest list includes an array of foreign aristocrats and dignitaries, including senior royals from Europe and Asia, as well as U.S. climate envoy John Kerry. Other likely attendees include Saudi aristocrats, as Rajwa’s mother comes from the same influential family as the late mother of King Salman. Her billionaire father owns a major construction firm in the kingdom.

Both Rajwa and Kate wore gowns by the Lebanese designer Elie Saab, said a spokeswoman for the company, Maryline Mossino.

The motorcade drove through Amman to the Al Husseiniya Palace, a 30-minute drive away, for the reception. There, the newlyweds walked beneath an arch of swords and were welcomed with a traditional zaffeh, a lively musical procession featuring drums, dancing, singing and clapping.

The royals greeted more than 1,700 guests at the reception, which featured live music and a banquet. The celebrations were capped with a fireworks display that could be seen across the capital.

Experts consider the marriage an advantageous alliance for the Hashemites, historic rivals of the Al Saud family to the east. Jordan has recently sought closer ties with Saudi Arabia and other Gulf Arab petro-states, which once doled out billions of dollars to the aid-dependent country but since have reined in their spending.

Even as restaurants blared call-and-response Arabic wedding songs and cars honked in celebration downtown, some signaled the royal fairy tale was fraught as Jordanians struggle to make ends meet.

Osama, a 25-year-old bookseller, was thrilled about the occasion and festooned his car and shop windows with portraits of the royal family. But he also knew reality would return quickly.

“Of course, it’s joyful,” he said, declining to give his last name for fear of reprisals. “But in a couple days, we’ll just go back to our problems.”