AMSTERDAM -- To the cheers of tens of thousands of people crammed shoulder to shoulder outside the royal palace here, Willem-Alexander of the House of Orange-Nassau became the Netherlands' first king in 123 years on Tuesday as his mother, Queen Beatrix, ended a 33-year reign with the stroke of a pen, signing the act of abdication in an ornate chamber at the palace.
Seated on a gilded chair and flanked by the Dutch cabinet, Beatrix, 75, became the third successive Dutch queen to abdicate, changing her title to princess as supporters celebrating the continuity of the monarchy thronged Dam Square outside the palace. Many had gathered for hours, clad in orange, the royal color, to watch the brief, long-planned and relatively low-key event on large television screens.
The day's events, a mix of tightly choreographed official pageantry and boisterous street parties across Amsterdam, helped lift the gloom created by a slumping economy, unpopular austerity measures and growing public recognition that, as the new king noted in an afternoon address, "it now seems less self-evident that the next generation will be better off than the last."
Dressed in an orange suit, Bart Koops, an executive at a bed company and a fervent royalist, joined the throng of other revelers early on Tuesday. "Monarchy is what unites us and makes us Dutch," Mr. Koops said. "This is a great day."
He added: "The monarchy is a point of stability and unity. Politicians just fight each other."
In contrast to the British royal family, he said, Dutch royals are far less formal, and they are in tune with the open, easygoing spirit of the Netherlands. "Look at the countries that don't have royalty," he said. "They are missing something."
Beatrix announced in January that she would step down to make way for a younger generation. After signing the formal declaration of abdication shortly after 10 a.m., Beatrix, the new king and his Argentine-born wife emerged onto a flower-bedecked balcony to cheers from the crowd. Church bells rang out across the city.
In the early afternoon, the crowd in Dam Square roared as King Willem-Alexander, trailing a long fur-trimmed cape, and his wife, Queen Maxima, entered the 15th-century Nieuwe Kerk, or New Church, next to the royal palace for the investiture ceremony.
Unlike royal rituals in England, there was no religious blessing or coronation.
Paying tribute to his mother and promising to continue her course, Willem-Alexander, 46, stressed the need to respect diversity and promised that "however varied our backgrounds, in the Kingdom of the Netherlands everyone can have a voice and can contribute to society on an equal footing."
He also acknowledged his subjects' growing economic woes as the country's once robust economy struggles with its third recession since 2009. Populist politicians have exploited this pain to press demands that the Netherlands halt immigration and crack down on welfare payments to foreign-born residents.
"I succeed to the throne at a time when many in the kingdom feel vulnerable and uncertain, he said, according to an official translation of his remarks. "Vulnerable in their jobs or their health. Uncertain about their income or the environment in which they live."
Before the swearing-in ceremony, the former queen clutched the hands of her son and daughter-in-law before the national anthem was played.
"Some moments ago I abdicated from the throne," Beatrix said, seeming to struggle with tears. "I am happy and thankful to present to you your new king."
Some of the cheers for the royal trio reflected the popularity of the new queen, who was born in Argentina and had a career as an investment banker before marrying Willem-Alexander in 2002, adding a dash of glamour and romance to an otherwise low-key and at times dowdy royal family.
More recently, Willem-Alexander has recovered from a scandal over his purchase of a holiday villa in Mozambique, which he sold last year. He is now widely seen as a sober-minded and responsible professional with a knack for connecting with ordinary people, Dutch experts said, but is also regarded as far less cerebral than his mother. He has mostly kept his views on society and politics to himself.
The new king is also Europe's youngest monarch, and as such he has vowed that he and Queen Maxima, 41, will not be "protocol fetishists." Dutch news media reported that the queen will attend the opening of a conference this summer on same-sex marriage, which has been legal here for years. On Tuesday, an anti-monarchist, Hans Maessan, stood in Dam Square waving a sign saying, "No Monarchy, More Democracy." Instead of sporting orange like those around him, he wore a white shirt that said "I Don't Want Him." He conceded that the balance of opinion was running against his cause but said that even republicans liked a good party.
Opinion polls, however, show overwhelming public support for the institution.
"Monarchy is a big part of our sense of ourselves," said Bas Heijne, a prominent Dutch commentator. "The Dutch don't want to do away with the monarchy. If you are rational you say: 'This is nonsense. We should get rid of it.' But the anti-monarchists underestimate the way the monarchy is part of Dutch life, of being Dutch."
Andrew Higgins reported from Amsterdam and Alan Cowell from London.
This article originally appeared in The New York Times.