Iolanthe Peverell was a medieval witch from Godric's Hollow and the granddaughter of Ignotus Peverell, one of the three brothers from The Tale of the Three Brothers. Her primary significance in wizarding history stems from her marriage to Hardwin Potter, which united the Peverell and Potter bloodlines. Through this union, she brought the Invisibility Cloak, one of the three Deathly Hallows, into the Potter family, where it was passed down as a family heirloom for centuries, eventually reaching Harry Potter. All known information about Iolanthe Peverell comes from supplementary material written by J.K. Rowling for the Pottermore website and is not mentioned within the original seven novels.
Born into the prestigious Peverell family, Iolanthe was the granddaughter of the legendary Ignotus Peverell. She lived in Godric's Hollow, the same village her grandfather had resided in. As her family's male line had died out, Iolanthe, being the eldest of her generation, inherited her grandfather's Invisibility Cloak (Pottermore). Iolanthe later married Hardwin Potter, a wizard from the nearby village of Stinchcombe. She explained to her new husband that the possession of the Invisibility Cloak was a family secret, a tradition started by her grandfather. Hardwin respected his wife's wishes, and together they established a new tradition: the cloak would be passed down to the eldest descendant in each subsequent generation of the Potter family. This ensured the Deathly Hallow remained in their lineage, eventually reaching James Potter I and, finally, his son Harry Potter (Pottermore).
Iolanthe Peverell's physical appearance is not described in any known source material. Similarly, aside from her respect for family tradition, nothing is known of her personality.
As a member of a prominent pure-blood family, Iolanthe was a qualified witch. However, no specific details regarding her magical abilities or skills are known.
Iolanthe Peverell is a character who does not appear or get mentioned in the seven original Harry Potter novels. Her existence and story were revealed by J.K. Rowling in an article titled “The Potter Family” on the Pottermore (now Wizarding World) website. Her character was created to provide a canonical explanation for how the Potter family came into possession of the Invisibility Cloak and to formally establish their direct lineage from the Peverell family.