Catherine Grandison, Countess of Salisbury

Catherine Grandison, Countess of Salisbury (c. 1304 – 23 November 1349) was an English noblewoman, remembered for her relationship with King Edward III of England and possibly the woman in whose honour the Order of the Garter was originated. She was the daughter of William de Grandison, 1st Baron Grandison, and Sibylla de Tregoz. Her mother was one of two daughters of John de Tregoz, Baron Tregoz (whose arms were blazoned Gules two bars gemels in chief a lion passant guardant or), maternal granddaughter of Fulk IV, Baron FitzWarin). Catherine married William Montacute, 1st Earl of Salisbury in about 1320.

Their children were:

According to rumour, King Edward III was so enamoured of the countess that he forced his attentions on her in around 1341, after having relieved a Scottish siege on Wark Castle, where she lived, while her husband was out of the country. An Elizabethan play, Edward III, deals with this incident. In the play, the Earl of Warwick is the unnamed Countess's father, though he was not her father in real life.

In around 1348, the Order of the Garter was founded by Edward III and it is recorded that he did so after an incident at a ball when the "Countess of Salisbury" dropped a garter and the king picked it up. It is assumed that Froissart is referring either to Catherine or to her daughter-in-law, Joan of Kent.

...
Wikipedia