Thank God for dutiful William in Catherine's hour of need. And how VERY different from an earlier Prince of Wales - who responded to his wife's grave illness by sleeping with young actresses and staying out in clubs until 3am...

Safe now in the sanctuary of their Norfolk home, Catherine, William and the children can look forward to a peaceful period of rest and recovery. 

The storm of publicity has passed and they will now take time as a family to concentrate on Catherine's recuperation.

As important as the princess's physical improvement is William's constant presence by her side, a vital contribution to her path back to full health.

How reassuring – and how very different from the story of another Princess of Wales, and another life-threatening illness.

A portrait of Albert Edward, Prince of Wales and later King Edward VII

The Prince of Wales  and his bride Princess Alexandra of Denmark just after their marriage, posing with Queen Victoria

The Prince of Wales in his uniform as colonel of the Tenth Hussars

Albert Edward, Prince of Wales, 1841 - 1910 seen here as an undergraduate at Oxford

Prince Bertie – the future King Edward VII – and his wife Alexandra suffered a similar shock when the princess suddenly fell ill as she was about to give birth to her third child and was diagnosed with rheumatic fever. 

Within hours her condition had worsened into a crisis.

Unlike Prince William, Prince Bertie paid scant attention to his wife's despair. Returning home from a trip to Russia he discovered her in pain and running a fever – but that didn't stop him taking off to a race meeting and a couple of dinners in Windsor.

Alexandra was left behind at Marlborough House, close by Buckingham Palace, and as she grew worse an urgent telegram was sent to Windsor calling Bertie back to London.

He didn't respond. Two more increasingly urgent telegrams were fired off, but still he took his time getting back to the capital - by which time it as clear the princess was very seriously ill, potentially one clinical stage away from death.

'She had dreadful pains in her leg and hip, and for days she lingered in the most pitiable state,' wrote the biographer Christopher Hibbert.

'The Prince of Wales was unconcerned [even though] his wife could not eat because her mouth was so painfully inflamed, and could not sleep without heavy doses of drugs.

'She turned pleadingly for comfort to [her lady in waiting] Lady Macclesfield who wept herself to see her crying so piteously from the dreadful pain.'

Yet the prince made light of it all, treating his wife's complaint as if it were no more than a chill.

'Most nights he went out, and if he sat with her he would grow bored and restless,” continued Hibbert.

'Irritated by the fussing anxiety of Lady Macclesfield Bertie would march out of the house to a club. Even when he told his wife he'd be back at a certain time, he was always late.'

The princess, refusing to take her sleeping-draught until he came to say goodnight, had sometimes to wait till three in the morning for the prince to roll back home.

Alexandra's illness dragged for months on but the prince's negligent attitude did not improve. 

He was out most nights in the company of women - 'notorieties' palace courtier Sir William Knollys called them - and nobody could rein him in.

Eventually the word got out, and people started gossiping about Bertie's neglect of his wife and inappropriate behaviour – he was seen publicly 'spooning with Lady Filmer', and ostentatiously taking young actresses out to supper before bedding them.

Indeed, his notoriously rampant promiscuity may have been the cause of his wife's tragic illness in the first place.

Eminent rheumatologist Dr Robert Pinals argued in a 2016 academic journal that the princess's condition deteriorated dangerously because the doctors got it wrong - Alexandra was suffering not from rheumatic fever but 'gonococcal arthritis [a sexually transmitted disease] – and that the infection was transmitted to her by her husband.'

It took almost six months for the princess to be well enough to greet her mother-in-law Queen Victoria from a wheelchair. The matriarch later wrote Alexandra 'looked lovely' that day, but altered. 

Her youthful optimism had taken a beating, and her leg was so stiff she would walk for the rest of her life with a pronounced limp.

Such is the way of fashion that some high-born ladies found the 'Alexandra limp' so fetching they adopted it themselves.

Her slight deafness now deteriorated into something much worse, and as the years went by it would grow increasingly profound until her whole social life had to be reconstructed because of it.

As time went on she became detached from life at court - 'her deafness grew progressively worse because of her illness and occasionally made her seem more stupid and less interesting than she really was,' wrote Hibbert, 'especially when she tried to conceal it by a continuous stream of talk which allowed no comment or reply.'

After the onset of middle age the royal couple – by now King Edward VII and Queen Alexandra - spent more and more time apart. 

The king's mistress Alice Keppel, great-great grandmother of Queen Camilla, largely took her place, being labelled by courtiers 'La Favorita'.

Alexandra as Princess of Wales, seated, with her daughters Victoria, Maude and Louise

An engraving of the young Prince of Wales in uniform, first published in1859

King Edward VII  pictured in full Coronation robes, having been crowned on August 9th 1902

Alexandra's friend the Countess of Antrim opined that if Alexandra had loved her husband as much as he loved her, he would have been more faithful.

But with her illness, the marriage had turned a corner and there was no going back.

When the wandering Edward died in 1910, Alexandra had the last word: 'Now at least I know where he is.'

The same will never be said about devoted Catherine and William.