By Milan Schreuer

New York Times News Service

To the long list of concessions that European monarchs have made to modernity, Belgium is adding another: submitting to a paternity test.

After refusing for months, King Albert II will soon give a DNA sample, his lawyer said this week, in a lawsuit brought by a woman who says she is his daughter, neglected and kept secret for decades.

King Albert, who abdicated the Belgian throne in 2013, will still fight to conceal the result.

The paternity test could mark a dramatic turn in a lawsuit that has been underway for years, exposing Belgium’s secretive royal family to unusual public scrutiny and criticism.

There is more at stake than just recognition. The case could also make the plaintiff, Delphine Boël, 51, an heiress to the king’s fortune, which is estimated to be worth hundreds of millions of dollars.

A court ordered the DNA test six months ago, but King Albert refused to obey, and last week a Brussels judge threatened to fine the king almost $5,600 a day until he submitted.

Belgium is a constitutional monarchy, where governing power rests with the Parliament, much like the systems in Britain, Spain, the Netherlands, Denmark, Norway and Sweden. The nearly 200-year-old monarchy remains a popular if largely symbolic institution.

The Constitution of Belgium essentially puts the king above the law, saying that he cannot be sued or prosecuted while acting as head of state.

Almost six years ago, King Albert ceded the throne to his eldest son, King Philippe, and soon after that, Boël filed her lawsuit.

She claims to be the child of an extramarital affair between her mother, Baroness Sybille de Selys Longchamps, and the future King Albert, who was then a prince, married to an Italian princess with whom he had three children. As Prince Albert, a second son who was not expected to reign, he enjoyed a life of party-hopping from castles to villas to yachts, and mingling with movie stars, models and fashion designers.

When Boël was born in 1968, the prince privately recognized her as his daughter and cared for her, according to her lawyer.

Things got more complicated in 1993 when his older brother, King Baudouin, died suddenly of heart failure at 63, leaving no children, and Albert became king. An out-of-wedlock child would have been an embarrassing distraction for a playboy prince, but for a king at that time, it could have been a scandal or a constitutional crisis.

King Albert phoned Boël and told her “now we cut all ties,” said Patrick Weber, a Belgian art historian and royalty watcher who has written several books on the monarchy and knows Boël.