There's a popular story in much of the English speaking world about King Alfred the Great of Wessex whereby he accidentally let a cake burn. I'm sure that you've heard some variation of the story before, but for those who haven't, after his kingdom was conquered by vikings and he was in hiding preparing to reconquer it, he was hiding in an old lady's house. While there, she asked him to watch the cake that she was baking, but he was distracted making military plans and so let it burn. Then she berated him for it and he showed his good nature by apologizing for it.
So did this actually happen (according to contemporary sources)? If it didn't happen, when did the myth first come about and how did it alter over time?
after his kingdom was conquered by vikings and he was in hiding preparing to reconquer it
The biggest problem with the whole 'Alfred and the cakes' story is that contrary to the story, Wessex doesn't seem to have been conquered by the Vikings at all. The raid happens at midwinter, which is unprecedented, and Wessex is taken by surprise, but the phrasing from the Anglo-Saxon Chronicle that states that Wessex submitted to the Vikings only appears in some of the manuscripts. For what it's worth, the idea that the invaders 'drove many over the sea, and the rest submitted' is lifted almost verbatim from Gildas' account of the Anglo-Saxon conquest of Britannia in De Excidio Britanniæ; a claim which is demonstrably false.
At the same time, a significant Viking force attacks Devon by sea, and is destroyed by the Devon fyrd, who inflict approximately 80% casualties on it. This alone tells us that one of the most significant counties of Wessex was more than capable of fighting back against the Vikings. That Alfred is joined by the Fyrds of Hampshire, Wiltshire and Somerset for his campaign at Easter implies that those counties were also sufficiently un-conquered that they were able to muster their garrisons and dispatch them for a campaign with Alfred's forces.
What is far more likely to have been the case is that, with the West Saxon garrisons stood down for winter, a Viking force was able to surprise Alfred and capture significant territory in Somerset, but was unable to proceed any further, and with the resumption of the campaign season in the spring, the fyrds of the other West Saxon counties mobilised and retook the lost territories. Of course, the story of a lost Alfred coming back from the brink of defeat is a far more heroic tale for the biography of the Cerdicing dynasty. And of course, the common touch of the story provides an interesting propaganda point.