He couldn’t know that at this very moment, people meeting up in secret all over the country were holding up their glasses and saying in hushed voices: ‘To Harry Potter - the boy who lived! - J.K. Rowling
"The Patronus is the most famous (and famously difficult) defensive charm. The aim is to produce a silvery-white guardian or protector, which takes the form of an animal." - Pottermore, The Patronus Charm.