question: Who is the maternal grandmother of John Woodville?
context: Title: John Woodville
  Passage: Sir John Woodville (c.1445 – 12 August 1469) was the second son, and fourth child, of Richard Woodville, 1st Earl Rivers, and Jacquetta of Luxembourg. In January 1465, Woodville's sister, Elizabeth, queen consort of King Edward IV of England, procured his marriage to Catherine Neville, Dowager Duchess of Norfolk (born c. 1400 – died after 1483), who was aunt to the powerful Richard Neville, Earl of Warwick. As the Duchess was about 65 years of age at the time and Woodville was only 19, the marriage was seen by all, particularly Warwick, as an indecent grasp for money and power by the Woodville family. One chronicler described it as a maritagium diabolicum (the diabolical marriage). In 1465, John was appointed Knight of the Order of the Bath by his brother-in-law, the King. In 1469, Woodville and his father accompanied King Edward on a march north, to put down what was thought to be a minor rebellion supporting Edward's brother the Duke of Clarence as the legitimate king. Before they met the rebels both Clarence and Warwick had announced their support for the rebellion; by the time the King met the rebels, the rebel force was far stronger than his. In a parley, the rebels told the King that they had no fight with him but advised him to distance himself from the Woodvilles. In no position to argue, the King sent the Woodville party away. Woodville and Rivers went first to the Rivers' house at Grafton and from there made their way westwards towards Wales. They were captured by Warwick's men on the western bank of the Severn and taken to Coventry in Warwickshire. Before leaving Calais to support the uprising, Warwick had published a manifesto citing the Woodvilles in general, and the Earl and John Woodville specifically, as his reason for supporting Clarence against the King. The publication of this manifesto was deemed, by Warwick, to justify the execution of Rivers and his son. They were beheaded on 12 August and their heads placed on spikes above the gates of Coventry. Woodville died childless.
  Title: Jacquetta of Luxembourg
  Passage: Jacquetta of Luxembourg, Countess Rivers (1415/16 – 30 May 1472) was the eldest daughter of Peter I of Luxembourg, Count of Saint-Pol, Conversano and Brienne, and his wife Margaret of Baux (Margherita del Balzo of Andria). She was a prominent, though often overlooked, figure in the Wars of the Roses. Through her short-lived first marriage to the Duke of Bedford, brother of King Henry V, she was firmly allied to the House of Lancaster. However, following the emphatic Lancastrian defeat at the Battle of Towton, she and her second husband Richard Woodville sided closely with the House of York. Three years after the battle and the accession of Edward IV of England, Jacquetta's eldest daughter Elizabeth Woodville married him and became Queen consort of England. Jacquetta bore Woodville 14 children and stood trial on charges of witchcraft, of which she was exonerated.
answer: Margherita del Balzo
citations: Jacquetta of Luxembourg John Woodville