Folio of Fortinbras

"It is my belief that great power is sealed inside of Hogwarts, but what kind of power, I do not know. Riches? Magic? An instrument of hope or death? I cannot say. A group of students and teachers alike formed a circle of trust. I fashioned an artefact to seal the identity of my closest co-conspirator."

- Excerpt from the folio of Fortinbras

The folio of Fortinbras was an ancient book owned by a former Charms Master of Hogwarts School of Witchcraft and Wizardry by the name of Professor Fortinbras, in which she penned down her fears and suspicions about the fabled Cursed Vaults. This book was retrieved from Classroom 2E where she left it behind centuries later during the 1987–1988 school year by Jacob's sibling. Although the ink on most of the pages

and subsequently used for their own research into their vaults while searching for their lost brother.