[1] In the proceedings of the cartulary of Auch (copies from the 13th century), Raymond-Aimeri, first baron of Montesquiou is described around 1096 as the younger brother of Guillaume Astanove Count of Fezensac.

Several Montesquiou were ruthless military commanders during the War of Religion, including Francois de Montesquiou, last baron of the senior branch, who murdered the prince de Condé at the battle of Jarnac, and the marquis of Montluc, field-marshal.

The marquis Anne-Pierre de Montesquiou-Fézensac held an important role in the French Revolution as a member of Parliament, renouncing noble privileges and later voting the beheading of king Louis XVI.

Hi older son, Elisabeth-Pierre de Montesquiou, joined Lafayette in the American war of Independence.

Count Robert de Montesquiou was a famous dandy in the turn of the 20th century, inspirer of Marcel Proust.