William VIII, Marquess of Montferrat

William VIII Palaiologos (Italian: Guglielmo VIII Paleologo; 19 July 1420 – 27 February 1483) was the Marquis of Montferrat from 1464 until his death.

He was the second son of Marquis John Jacob and Joanna of Savoy, daughter of Amadeus VI of Savoy.

William inherited the Marquisate after the death of his elder brother John IV. He obtained, by Emperor Frederick III, the territories lost to Savoy from 1435. William served as condottiero for Francesco I Sforza of Milan and fought alongside him at the battle of Caravaggio(1448) and was afterwards rewarded with the lordship of Alessandria.

In 1449, William was accused of treachery and imprisoned by Francesco Sforza. The reason was said to because he had formed an attachment to Sforza's wife Bianca Maria Visconti. He was released a year later. Angry over his treatment by Sforza, William encouraged his brother John IV of Montferrat and relative Louis of Savoy to make war on Sforza (and Milan), and then he himself would lead the troops in battle. This attempt failed.

William later became a tutor to the couple's son Galeazzo Maria. Following his assassination, William held several positions in the Duchy of Milan.

Marriages and issue William had three wives.

On 19 January 1465, he married Marie de Foix (1452 - May 1468), daughter of Gaston IV, Count of Foix and Eleonor of Navarre. They had:

Giovanna of Montferrat (1467 - 1490). She married Ludovico II of Saluzzo.

On 18 July 1469 he married Elisabetta Maria Sforza (1456 - 1472), daughter of Francesco Sforza, Duke of Milan, and Bianca Maria Visconti. They had:

Blanche of Montferrat (1472 - 1519), married Charles I of Savoy

On 19 September 1474, he married Bernarde of Brosse (1450 - 1485), daughter of John II of Brosse and Nicole, Countess of Penthièvre. They no had issue.

William had also at least three illegitimate children:

Annibale (1460 - 2 February 1523). Lord of Frassinello and abbott of Lucedio; Lucrezia (died in 1508). She married firstly Giovanni Bartolomeo del Carretto and secondly Rinaldo d'Este, natural son of Niccolò III Este; Margherita. She married Hector de Monteynard (murdered on 31 July 1501).