Actors staged a re-enactment of the November 30, 1813 arrival of Prince Willem Frederik -- later King Willem I, the ancestor of current King Willem-Alexander -- at a Hague beach, followed by pomp and ceremony at the official opening of the celebrations at a medieval hall near the Dutch parliament.
"Today, 200 years ago in 1813, the seed was sown for what would later become the Kingdom of the Netherlands," King Willem-Alexander said in a speech at the historic Knights' Hall, which stands cheek-by-jowl to the Dutch parliament in The Hague.
"Happy birthday," Dutch Prime Minister Mark Rutte added, saying Saturday marked the official birth of the modern Dutch constitutional monarchy.
Prince Willem Frederik's 1813 landing at the beach at Scheveningen, today a popular seaside suburb, is widely seen as setting in motion the formation of the modern Dutch state.
The prince arrived there after 18 years in exile under French rule, which ended with Napoleon Bonaparte's defeat at the Battle of Leipzig a month before, in October 1813.
Napoleon's loss resulted in the destruction of much of what was left of French power in the Netherlands, Germany and Poland.
Prince Willem Frederik was crowned as King Willem I of the united Netherlands in 1815.
"Today we are celebrating what we've achieved over 200 years," Rutte said.
King Willem-Alexander, who took over from his mother, Princess Beatrix, in April this year and attended the ceremony with his wife, Queen Maxima, was presented a commemorative book. A classical orchestra then played a song composed for the occasion.
King Willem-Alexander remains the head of state, but the country is today ruled by decisions made by the Dutch parliament.
The bicentennial celebrations will continue on various dates over the next two years, ending in September 2015 in the Dutch capital Amsterdam, organisers said.
The calendar includes festivities on Saint Martin, which together with Curacao and Aruba forms part of the Kingdom of the Netherlands in the Caribbean.