Short answers, pulled from the story.
Lady Margaret Butler was born around 1454 within the stone walls of Kilkenny Castle in County Kilkenny. Her birth placed her at the center of a decades-long legal and military feud over the Earldom of Ormond.
Lady Margaret Butler married Sir William Boleyn before the 2nd of November 1469. This union produced ten children and forged a path to the highest levels of English society.
Lady Margaret Butler was declared by inquisition to have suffered periods of insanity in the years 1538 and 1539. This legal finding rendered her incapable of managing her own estates and complicated the management of her vast holdings.
Lady Margaret Butler died on the 12th of March 1539. After her death, Hever Castle was given to Anne of Cleves in 1540, marking the end of an era for the Boleyn family in England.
In the 2002 Philippa Gregory novel The Other Boleyn Girl, Margaret Butler appears as Grandmother Boleyn, a character portrayed as critical, insubordinate, and shrewd. The novel places her in the Boleyn estate at Hever Castle where she offers a perspective that bridges the gap between the Irish nobility and the English monarchy.