Nephew of Earl of Halifax. He is in this timeline because of his friendship and correspondence with Horace Walpole   [1]   [2]   [3]   [4] , which resulted in an immense record, including much Montagu family information.

Horace Walpole was a writer and the Pepys of his day. The UCSC library must have 4 yards of books containing collections of Walpole's letters. Many of these letters are to or from George, and there are 2 volumes devoted to Montagu correspondence. The index of The Yale Edition of Horace Walpole's Correspondence contains 20 pages under Montagu.

The Montagu's enlisted Walpole on occasion to perform genealogical research, so Walpole collected Montagu family trees, checked into connections, etc.. For instance, Walpole was asked, when in Paris, to check into any connection with Jean de Montagu/Montaigu (1349-1409). It may be that the purpose of this genealogy was to support some interesting architecture at the Montagu estate at Boughton, in Northamptonshire. Apparently, large Montagu "genealogies" consisting of lists of shields (heraldic lineages) were used both on a fireplace chimnypiece and a staircase (the staircase apparently had one arms per tread).

George was educated at Eton. George, Walpole, and Charles Lyttelton formed what Walpole called the Triumvirate. George was an M.P. for Northampton. Late in life George and Walpole had a falling out due to political differences.

George was considered "extremely indolent" and was still a midshipman at 60. Some considered him to have spent his whole life as a side-kick to his elder brother, Charles. I will include some of his writing below. Clearly, the complete letters are of interest to historians.

"I am becoming a very Capulet, and will change my name with the first man I meet, if he has a permit from the Chief Justice."

"Truly I am so far from being dead I never was so lively, because freed from the mortal vexations of these horrid times. To amend them it is not in my poor power; to be witness to the daily progress of the hateful junto would exceed my patience. I hang not up my harp upon the mournful willow, but touch its tenderest mournfullest string when I get an intelligent and courteous hearer, and make my daily orisons before the pictures of John Hampden and Algernon Sidney   [2]   [3]   [4] , with my hours of Magna Carta in my hand."

"You know my old hankerings for Lady Mary Churchil; therefore you did kindly by me to give me the earliest notice of her going to be in the neighbourhood. No one can be more delighted than I am, and you may so tell her when you see her..."

"I also hope you are as well though not so fat as I am..."

"I have not wrote to congratulate my cousin. I cannot compliment where I don't esteem. ... The great Lord Halifax my uncle lived in harmony with his family, was the patron of the worthy and witty men of his age, and died rich and regretted. My his end be the same!"

W.S. Lewis, an editor of Walpole's, noted:

"Mr George Montagu, who used many odd expressions, called his own family, the Montagus, the Cu's."

Walpole himself adopted this, for instance:

"George Montagu and the Colonel have at last been here, and have screamed with approbation through the whole Cu-gamut."

Sources:
The Yale Edition of Horace Walpole's Correspondence.
Letters of Horace Walpole, Lewis.

http://www.montaguemillennium.com/familyresearch/h_1780_george.htm