The first Dutch king in more than a century has pledged to use his ceremonial position as head of state to help steer his country through uncertain economic times.
The generational change in the House of Orange-Nassau gave the Netherlands a moment of celebration, pageantry and brief respite as the country of nearly 17 million struggles through a lengthy recession brought on by the European credit crisis.
Visibly emotional, the much-loved Queen Beatrix ended her 33-year reign in a nationally televised signing ceremony as thousands of orange-clad people cheered outside. Millions more were expected to watch on television. Just over four hours later, King Willem-Alexander, wearing a fur-trimmed ceremonial mantle, swore an oath of allegiance to his country and the constitution in the historic New Church.
In a speech Europe's youngest monarch underscored the ceremonial nature of his monarchy in this egalitarian society but also the symbolic and economic value a king can deliver on state visits aimed at drumming up trade. "I will proudly represent the kingdom and help discover new opportunities," he said.
The investiture ceremony was the final formal act on a day of high emotion within the House of Orange-Nassau and was to be followed by an evening boat tour around the historic Amsterdam waterfront.
The former queen becomes Princess Beatrix and her son becomes the first Dutch king since Willem III died in 1890.
The 46-year-old king's popular Argentine-born wife became Queen Maxima and their eldest of three daughters, Catharina-Amalia, became Princess of Orange and first in line to the throne.
Amsterdam resident Inge Bosman, 38, said she doubted Willem-Alexander's investiture would give the country much of an employment boost. "Well, at least one person got a new job," she said.
Security was tight with thousands of police - uniformed and plain clothes - and an untold number of civil servants assisting in the logistics. Police arrested two protesters on Dam Square - one of them wearing a white shirt indicating he was a republican - shortly after the abdication for not following officers' orders to leave. Amsterdam police released both without charge shortly afterward and apologised for detaining them.
At an anti-monarchist demonstration on the nearby Waterloo Square, protestors dressed in white instead of orange and carried signs mocking Willem-Alexander.