During the ’45 Prince Frederick took no active part in the military process, unlike his younger brother the Duke of Cumberland. He did directly ask for the command of the army heading to face Prince Charles Edward Stuart and was refused, understandably so, as he had never been allowed to see any military action and so was completely inexperienced. But he took it as a personal rebuff, and was deeply hurt. As a result he showed a lack of any interest in the rising, going to the theatre as usual, and engaging in a sugar-plum bombardment of a marzipan model of Carlisle Castle as a joke, at the same time as Cumberland was advancing on the real castle. Now it’s easy to see this as a reaction to rejection, but at the time some thought he might be a Jacobite sympathiser, even though it was a somewhat ridiculous idea. Had the Jacobites won, Frederick too would have lost his chance to one day be King of Great Britain.

Prince Frederick as an adult
After the ’45 he was very merciful to the prisoners, going to pay respects to Flora MacDonald, trying to intervene to save the life of Lord Cromarty and preventing the censure of Oxford University. Later he included known Jacobites in his entourage, and seems to have done his best to quell the wave of brutality and severity that followed the rising.
Frederick had for some years attracted a political following of those who were unhappy with the king’s and current government’s policies, and in 1747 decided to set himself up in opposition at the general election. He provided funds to purchase seats and votes, and wrote up a manifesto, which was published under his name.
This was a serious enough threat to the establishment that the Duke of Newcastle and his brother the Prime Minister were very alarmed, and asked the king to intervene. King George refused, not out of loyalty to his son, but because he had no liking for the Pelham family.
In the end the prince’s opposition, though winning him about one hundred seats, was insufficient to have any power at all. But he continued to make his presence felt and remained involved in politics, and was taken seriously by the large number of courtiers who were aware of the age of King George and that Prince Frederick would one day, maybe soon, be the king.

Frederick, Prince of Wales by Thomas Frye, mezzotint, published 1741
For his part Frederick must have been aware that the king would far prefer the Duke of Cumberland to succeed him on his death than his eldest son, although in fairness to Cumberland, he never expressed the slightest inclination to usurp Frederick’s place as heir.
Prince Frederick clearly thought he would probably be king before the next general election was held, and with King George again in Hanover in 1750, began to draw up plans for that eventuality, which would include dissolving parliament, holding another election, and making sure that none of his children could openly oppose him as he ascended the throne.
However, none of these plans or those of his followers came to be, because, completely unexpectedly, on 20th March 1751 (31stNS) Prince Frederick died. The cause of his death has been disputed ever since. One story has it that he was hit in the chest with a cricket ball some years before, and that it was the resulting injury that eventually killed him. Another story says that got very wet and cold working in his garden, then went straight to attend a ceremony, wearing hot and heavy formal robes, and then once home, sat on a couch by an open window, and thus caught the chill which killed him.

Prince Frederick, 1740-50.
He certainly did contract a severe chill for which he was bled and blistered, and although he had a nasty cough, seemed to be recovering, when all of a sudden whilst chatting with friends one evening he began to cough uncontrollably, seized his stomach and died. The post mortem found a burst abscess in his chest (hence the cricket ball theory).
He was buried in Westminster Abbey and is now mainly remembered by the lampoon of an epitaph, probably written by a Jacobite:
Here lies poor Fred, who was alive and is dead;
Had it been his father, I had much rather;
Had it been his brother, still better than another;
Had it been his sister, nobody would have missed her;
Had it been the whole generation, so much better for the nation.
But since it is Fred, who was alive and is dead,
There is no more to be said.
It’s a bit unfair of him to be remembered this way. It’s true that to the average citizen of Britain his death did not make much difference to their lives. To history it is his inferior side that he’s remembered by, as a rake, practical joker and ineffectual member of the royal family. But his friends had quite a different view of him, and he was certainly a caring husband and parent, was generous and sensitive, and far more humane than his brother Cumberland, very attached to Great Britain, and assertive of the rights of its inhabitants.
He may well have been a far better king of the country than either his father or grandfather were. Sadly we will never know.