Sirius Black's daily letters to Harry Potter

These letters were written daily from June 13 1995 until the thrid task of the Triwizard tournement. They were all written to his godson, Harry Potter, in hopes of reminding Harry "that whatever happened outside the walls of Hogwarts was not Harry's responsibility, nor was it within his power to influence it". The letter that arrived on the day of the Third task was, however, just a muddy footprint, and was an attempt at a "good-luck charm".

Letter one
If Voldemort is really getting stronger again, he wrote, my priority is to ensure your safety. He cannot hope to lay hands on you while you are under Dumbledore's protection, but all the same, take no risks: Concentrate on getting through that maze safely, and then we can turn our attention to other matters.

Letter two
A muddy pawprint as a "good-luck charm".