So little is known of the domestic relations of the Montagus that it is hazardous to advance a conjecture.  One writer has suggested that there was a quarrel over money, but there are no grounds to support this.  Another has it that Lady Mary’s flirtations or intrigues did not meet with her husband’s approval.  Yet another thinks that Montagu found his wife with her sharp tongue, very ill to live with.

The Montagus had been married for seven-and-twenty years; their younger child was now twenty-one.  Since Montagu assisted Lady Mary as a girl with her Latin studies, they do not seem to have had much in common.  Lady Mary cut a figure in the social world; Montagu was a nonentity in political life and seemed content so to be.  Perhaps they were tired of each other, and welcomed a separation that at the outset was intended only to be temporary.  “It was from the customs of the Turks that I first had the thought of a septennial bill for the benefit of married persons,” Lady Mary once said to Joseph Spence; and it is more than likely that she would have taken advantage of such an Act of Parliament had it been in existence.

That there was no definite breach is evident from the fact that husband and wife corresponded, though it must be confessed that her letters to her husband are almost uniformly dull, except when the topic is their son.  On the other hand, there was certainly no especial degree of friendship between them, and in one of her letters Lady Mary said pointedly:  “You do not seem desirous to hear news, which makes me not trouble you with any.”  For the rest there are descriptions of the places which Lady Mary visited and an account of the people she met.

Lady Mary proceeded from Dover to Calais, and thence to Dijon, where she arrived in the middle of August.  Wherever she went she found herself among friends.  “There is not any town in France where there is not English, Scotch or Irish families established; and I have met with people who have seen me (though often such as I do not remember to have seen) in every town I have passed through; and I think the farther I go, the more acquaintance I meet,” she told her husband.  At Dijon there were no less than sixteen families of fashion.  Lord Mansel had lodgings in the house with her at Dijon, and Mrs. Whitsted, a daughter of Lord Bathurst, resided in the same street.  She met Lady Peterborough, and just missed the Duke of Rutland, at St. Omer.  At Port Beauvoisin she ran across Lord Carlisle.

From Turin, she travelled, on the advice of Lord Carlisle, to Vienna, which he declared was the best place in Italy in which to stay.  The fact that it was the intention of Lady Pomfret to remove from Sienna to Vienna was the deciding factor.  She liked the latter city so well that she remained there until August of the following year (1740).  It had one great merit in Lady Mary’s eyes, that it was cheap.  Next to that, she derived pleasure from the consideration with which she was treated.