Welcome to Harry Potter Theory. Today, we’re going to be discussing a notoriously difficult spell to cast- the Patronus Charm. Specifically, we’ll be addressing all KNOWN Patronuses assigned to Harry Potter characters, and exploring what those Patronus animals mean. 
It was the Prisoner of Azkaban that first introduced the idea of Patronuses- spirit guardians produced via the complicated spell Expecto Patronum. Expecto Patronum is typically used to ward off dementors and in Fantastic Beasts we are informed that the patronus is also used to ward off Lethifolds. In most circumstances the patronus charm will generally appear as white vapour. However, in some instances, when the witch or wizard is talented enough, expecto patronum will produce a silvery-white animal shape which is known as a corporeal Patronus. 
The Patronus represents hope, happiness, survival and purity, which is why it’s so offensive to Dementors, and can also be used as a communications device- a notable example of this being when Snape used his patronus to guide harry to the sword of gryffindor in the forest of dean.
If you asked any member of the faculty at Hogwarts: School of Witchcraft and Wizardry, they’d quickly tell you it’s one of the most difficult spells that a wizard or witch could cast.
Even though Harry managed to master it when he was only 13 years old, many other wizards didn’t. In fact, it wasn’t uncommon for adult wizards and witches to fail to produce even a formless Patronus, as shameful as the thought might be.
So today, I thought we’d take a look at the historical records, and track down every single  Patronus and their caster from the wizarding world, from the massive Wooly Mammoth that Hedley Fleetwood conjured, to the boar of Ernie Macmillan.
Bear in mind that NOT EVERYONE we know has been able to cast a Patronus successfully, so you won’t necessarily see all of your favourite characters on the list.
Let’s get in to it.