( CNN ) -- Seven people were killed when a car careered into a crowd of people watching the Dutch royal family riding past in an open-top bus Thursday . Queen Beatrix began her reign in 1980 after her mother abdicated the throne . The incident occurred during Queen 's Day , a national holiday celebrated every April 30 to mark the queen 's birthday . The birthday of Queen Beatrix -- the current monarch -- is actually January 31 . The celebrations are a reflection of how widely popular members of the royal family remain in the country as national figureheads . They have no political power , but hold a large number of ceremonial duties . The Netherlands only became a kingdom with its own monarch in the early 19th century . However , Queen Beatrix descends from the Nassau and Orange dynasties which ruled the area as stewards for six centuries . The House of Nassau 's role dates back to 1403 , when Count Engelbrecht I of Nassau married Johanna van Polanen , the lady of Breda . As they acquired more land , they entered the ranks of the highest nobility and a series of deaths and inheritances saw the German-born Prince William I found the House of Orange Nassau in the mid 16th century . In 1688 England invited the then Dutch stadtholder ( steward ) , the above William 's grandson , William of Orange , whose wife Mary was a Stuart , to rule England . In 1795 the last Dutch stadtholder , Prince Willem V , was forced to flee to England when the French invaded . The area remained part of the French Republic , and later Napoleonic Empire , until 1815 , when Prince Willem V 's son established the Netherlands , becoming King Willem I . His grandson , William III , was the kingdom 's last male ruler . When he died in 1890 , his wife , Emma , became regent for nine years , until their daughter Wilhelmina was old enough to accede to the throne . Wilhelmina 's 50-year rule took in both world wars . However , as has become the norm with Dutch monarchs , she abdicated in 1948 to allow her daughter , Juliana , to take the throne . Queen Juliana would famously dress in casual clothes and ride her bike to visit friends . She reigned until 1980 , when she abdicated to allow Beatrix to begin her reign . Queen Beatrix , now 71 , married the German diplomat Claus von Amsberg , a source of protests at the time as he had served in the German Wehrmacht during World War II , in 1966 and they had three sons : Willem-Alexander ( born 1967 ) , Friso ( born 1968 ) and Constantijn ( born 1969 ) . Prince Claus became a very popular figure before passing away on October 6 in 2002 . Queen Beatrix has indicated that she wo n't be abdicating in the near future , as she wants Crown Prince Willem-Alexander and his wife , Princess Maxima , to spend time with their family .
kingdom only became Netherlands with its own monarch in early 19th century . Queen Beatrix descends from the Orange and Orange dynasties . There has not been a French king since William III in early 19th century .