Mary II, Countess of Menteith

Mary II of Menteith was the Countess of Menteith. Her father was Alan II, Earl of Menteith, who died c. 1330. She is believed to have agreed with her kinsman Murdoch de Monteith, in 1330, that he should hold the Earldom, but when he was killed in July 1333, Mary assumed the title. She married Sir John Graham (d. 28 February 1347), who in her right became Earl of Monteith and assumed the title in May 1346. She died sometime prior to 29 April 1360. She was the mother of Margaret Graham, Countess of Menteith.

...
Wikipedia