Norway's Princess Mette-Marit has had surgery - a lung transplant at the National Hospital in Oslo. The operation is a response to a chronic lung disease she has suffered from for years, now understood to be pulmonary fibrosis. The palace announced that the procedure has gone well so far, but that this is only the first step in a long and difficult treatment.

The deterioration had been visible for months. The princess increasingly missed official engagements, and when she did appear, she wore oxygen to get through. At the Constitution Day celebration in May this year she looked exhausted, with a persistent cough - a picture anyone could read without an official diagnosis. When a public figure appears on an oxygen mask for that long, press releases about being "in good shape" stop convincing anyone.

The head of thoracic surgery, Arne Fiane, said the "transplant has been successful so far", while the head of pulmonology, Are Holm, explained that the princess would remain in hospital for several more weeks - a standard procedure for adjusting therapy and rehabilitation. Prince Haakon cleared his agenda to be by her side.

Behind the protocol calm of any court lies the same human reality, and it doesn't pick an address. Illness doesn't ask about titles, and a lung transplant is a hard operation for anyone - princess or not. The Norwegian court has spent years building the image of a modest, down-to-earth monarchy; the way it handles this crisis will show how much of that image is real and how much is just a well-managed picture.