A continuation of "Friends and lovers."
Princess Docile and Prince Somber
That Lady Mary's marriage to Edward Wortley Montagu was emotionally unfulfilling seems clear. In later life Lady Mary wrote a fable about Princess Docile and her suitor Prince Somber. Prince Somber seems to be based on Wortley; he treats women "with a coldness verging on Contempt." 
Wortley's coldness as a suitor seems to have extended into the marriage. In October 1712—just two months after their elopement—Lady Mary was complaining to Wortley of his neglect after he had gone to the north of England without her; left behind, she sent after him letters that went unanswered. "I sometimes imagine you not well," she wrote, "and sometimes that you think it of small importance to write, or that greater matters have taken up your thoughts. — This last imagination is too cruel for me....How can you be so carelesse?" And on their first anniversary, she began a letter to him, "I can not misse an Oppertunity of saying kind things to you thô you will never make use of one to say them to me. How could you write me so ungracious a letter? why Would you do it?" 
Their adventure in Turkey seems to have temporarily brought them closer; Lady Mary became pregnant with their daughter around the time she visited the harem and saw dances that made her think of "something not to be spoke of" (see Part 3 of this series, "In the harem"). But after their return from Constantinople Wortley increasingly found reasons to be away on business. Lady Mary's public profile, and the vicious attacks on her by Pope and others alleging sexual improprieties, may have estranged the couple further.
At some point after their experiences in the Ottoman lands Lady Mary composed a "little treatise" that she later described to Joseph Spence: "It was from the customs of the Turks that I first thought of a septennial bill for the benefit of married persons..." The "septennial bill" would ensure that "every married person should have the liberty of declaring every seventh year whether they choose to continue to live in that state for another seven years or not..." It's an obvious point, but someone content in their marriage is less likely to be thinking about the advantages of having the right to dissolve it at will. 
"I find you so different from the rest of mankind": Francesco Algarotti
Enter Francesco Algarotti, a young Italian intellectual who arrived in London in the spring of 1736. Young, handsome, intellectually daring and a sparkling conversationalist, he dazzled both Lady Mary and her friend Lord Hervey; soon both were utterly smitten with him. In August Lady Mary declared in a letter to Algarotti, "I no longer know how to write to you. My feelings are too ardent; I could not possibly explain them or hide them...I see all its folly without being able to correct myself." 
Folly indeed. Not only was Algarotti half her age (at the time of his arrival he was 23, while she was 46), he seems to have had a decided preference for male lovers. Since her own close friend Lord Hervey was probably one of them, Lady Mary is likely to have been aware of this preference. Nonetheless, she wrote a remarkable letter to Algarotti when she learned of his plans to return to Europe. Comparing herself to Queen Dido being abandoned by Aeneas (although perhaps a more apt comparison would have been to the apocryphal tale of Sappho's unrequited love for Phaon in Ovid's Epistles), she wrote,
I like everything in you, and I find you so different from the rest of mankind...that it does not surprise me that you have inspired sentiments which until now have not been inspired in anybody...Algarotti did not return to London for more than two years. In the intervening time he published a book of philosophical dialogues, Il Newtonianismo per le dame (Newtonianism for women, Naples, 1737). In 1742 it was translated into English by Elizabeth Carter as Sir Isaac Newton's theory of light and colours, and his principle of attraction, made familiar to the ladies in several Entertainments. In the fourth Entertainment there is a brief tribute to Lady Mary's pioneering inoculation efforts: "How many, as well fair Circassians as English Beauties, have had their Charms preserved by the Inoculation of the Small Pox..."  (See "Charm'd with their Civility and Beauty," part 2 of this series, for more about Lady Mary's role in bringing smallpox inoculation to Britain.)
My reason makes me see all its absurdity, and my Heart makes me feel all its importance. Feeble Reason! which battles with my passion and does not destroy it, and which vainly makes me see all the folly of loving to the degree that I love without hope of return.
...you must believe that you possess in me the most perfect friend and the most passionate lover. I should have been delighted if nature permitted me to limit myself to the first title; I am enraged at having been formed to wear skirts.
Why was my haughty Soul to Woman joyn'd?
Why this soft sex impos'd upon my Mind?... 
"I am leaving to seek you"
During Algarotti's absence Lady Mary sent him anguished, abject letters imploring him to write; these letters make for difficult reading. He did ultimately return to London in 1739 for a second visit. His sojourn lasted about three months, some of it spent staying with Hervey. During this visit, Lady Mary wrote an erotic poem in which the speaker imagines watching a lover sleep:
Between your sheets supine you sleepGiven her own recognition that her love was "fruitless," what happened next is extraordinary. On 16 July, about two months after Algarotti had left London to travel to Russia, she wrote him, "I am leaving to seek you. One need not accompany such a proof of an eternal Attachment with an embroidery of words. I shall meet you in Venice."  A few days later she left England for the Continent, not to return for more than two decades. Perhaps unsurprisingly, though, her fantasy of living with Algarotti was never realized.
Nor dream of vigils that fond Lovers keep
While wakeing I indulge the pain
Of Fruitless Passion oft declar'd in vain... 
"I have begun to scorn your scorn"
Algarotti spent much of the next two years at Frederick the Great's Prussian court in Berlin, and acting as his ambassador to other European kingdoms. In that capacity he journeyed to Turin 1741. Having waited in vain for him to come to Venice for nearly two years, Lady Mary went there to meet him. Her visit lasted almost two months, and they were in close contact: Algarotti apparently gave her a poem on the subject of love that was later found in her copy of the 1741 edition of Madame de La Fayette's La Princesse de Clèves, and he added some brief notes to her letters to Lord Hervey. But this visit disabused Lady Mary of the illusion that Algarotti was capable of returning her romantic feelings. After he left Turin, she wrote him a final letter:
I have begun to scorn your scorn, and in that vein I no longer wish to restrain myself. In the time (of foolish memory) when I had a frantic passion for you, the desire to please you (although I understood its entire impossibility) and the fear of boring you almost stifled my voice when I spoke to you, and all the more stopped my hand five hundred times a day when I took up my pen to write to you. At present it is no longer that. I have studied you, and studied so well, that Sir [Isaac] Newton did not dissect the rays of the sun with more exactness than I have deciphered the sentiments of your soul...I saw that your soul is filled with a thousand beautiful fancies but all together makes up only indifference...About manuscripts, statues, Pictures, poetry, wine, conversation, you always show taste, Delicacy, and vivacity. Why then do I find only churlishness and indifference? Because I am so thick as to strike out nothing better... To Hervey she wrote that her visit to Turin was "a very disagreable Epoque of my Life." She would not meet or correspond with Algarotti again for fifteen years. 
"You can hide the passions, never will you succeed in exterminating them"
Lady Mary spent the next two decades living and travelling in Italy and southern France. She remained on cordial, if emotionally as well as physically distant, terms with her husband (who apparently had no clue about Algarotti), and received £1200 a year from him for living expenses. She spent most of this time in quiet retirement near Brescia, where perhaps she was too isolated. She wound up becoming the victim of Count Ugolino Palazzi, who exploited her financially and, when it became clear that she wanted to return to Venice, tried various stratagems to prevent her from leaving; she only escaped with difficulty. (Palazzi and his brothers would later be convicted of "violent outrages against their tenants, including murder." )
Stopping at Padua on her way to Venice at the end of 1756, she was reunited with Algarotti, who had an estate in the area. Her friendship with him was renewed, along, perhaps, with the dim embers of that passionate attraction which once caused her so much pain. (She was now 67, while he was in his mid-forties.) Her letters to him from Venice have a bantering, flirtatious tone, but nonetheless express deep feeling:
Farewell Philosophy: here are the fine beginnings of Dotage. I gave proof of it last night at the academy of M. Barbarigo in the presence of three or four hundred people. There was excellent Music. Perhaps you do not know that I love Music to the point of Hatred. I could not listen to it with impunity...I have kept myself as distant as I could from that charming seductress, and I flattered myself that my weakness was not known. Poor human Wisdom! it is your ultimate effort: you can hide the passions, never will you succeed in exterminating them. This Reflection smells terribly of Marivaux. —Lady Mary alternated spending time in Venice (during the Carnival seasons) and Padua (during the summers) until two events finally called her back to England. The first was the death of her husband Wortley in January 1761, and familial struggles over his will (which left the bulk of his fortune, more than £1 million, to his second-oldest grandson, rather than to his own estranged son). Second was her own ill health: she discovered, probably just weeks before Wortley's death, that she had breast cancer.
Let us return to my Story. I abandoned myself to the Pleasure of listening to enchanting sounds which stir the soul, thinking mine frozen enough by time to be able to resist even the Sirens. Mademoiselle Barbarigo with her Angelic face joins her voice with the Instruments, the Applause is deserved and general; her mother's eyes sparkle with joy. A certain Chevalier Sagramoso (whom I shall hate all my life) whispers to me, out of an accursed Politeness, that he had heard my daughter sing in London. A thousand pictures present themselves at the same time to my mind, the Impression becomes too strong and, fool that I am, I burst into tears, and am obliged to leave in order not to disturb the concert by my sobs. I return home, exasperated at having drawn public scorn on myself deservedly: a sentimental old woman, what a Monster! 
Her friend, the older writer Mary Astell, had undergone a mastectomy in 1731 (without anesthesia, which was not developed for another century). Astell had died in agonizing pain two months after the operation. Lady Mary decided against any but palliative treatments, although she knew that the cancer was likely to prove fatal within a year or two. After a final summer in Italy, in September 1761 she set out for London.
"Dragging my ragged remnant of life to England"
But "dragging [her] ragged remnant of life to England"  was complicated by the continuing war in Europe. Britain was allied with Prussia against France, Spain, and the Austro-Hungarian Empire; Lady Mary's route inevitably passed through hostile or contested territory. It was a long and hazard-filled journey. But by mid-November she had arrived at the port city of Rotterdam, where she stayed for two months while waiting for an opportunity to cross the Channel. It finally came in mid-January 1762; by the end of the month she was living in a house in London near that of her daughter Lady Bute.
Lady Mary's final months were spent re-acquainting herself with her family and her old friends, and coming to know some of the new members of London's fashionable and political worlds who had emerged in the two decades of her absence. But by summer she was very seriously ill. In her last days she gave the volumes of her lifelong journals to Lady Bute. Her daughter apparently read and re-read the journals, and allowed her own youngest daughter, Lady Louisa Stuart, to read the early volumes "with copying or note-taking expressly prohibited." But shortly before her own death in 1794, Lady Bute had all of Lady Mary's diaries burned. 
Lady Mary died on 21 August 1762, just two days shy of the fiftieth anniversary of her elopement with Edward Wortley Montagu. She had not had an easy life. But she had become a highly regarded poet, a thought-provoking essayist, a dangerous wit, an intrepid traveller, and an intellectually and sexually adventurous woman during a time in which it was increasingly difficult for women to escape conventional family-oriented roles. As her biographer Isobel Grundy has written, "her intellect made her hated...and her emotional sensitivity made her suffer." But towards the end of her life she wrote that "there is no happiness without an alloy, nor indeed any misfortune without some mixture of consolation, if our passions permitted us to perceive it." 
Coda: The Embassy Letters
In December 1761, while she was stranded in Rotterdam, Lady Mary entrusted the two manuscript volumes of her account of her experiences in the Ottoman lands to the Reverend Benjamin Sowden, a British Presbyterian minister. Her intention was apparently for Sowden to have them published. But after her death, Sowden contacted Lord Bute about the volumes. Horace Walpole reported that "her family are in terrors" about what they might contain. Lady Mary's son-in-law Lord Bute paid Sowden £200 for the manuscript, which was duly surrendered. 
But Sowden had allowed two English travellers who had expressed interest in the manuscript to borrow it overnight, and they managed to transcribe it before returning it. Without the family's knowledge or approval, Letters of the Right Honourable Lady M—y W—y M—e Written during Her Travels... was published by Becket and De Hondt in three volumes in London in 1763, and became a sensation. Known as "The Turkish Embassy Letters," the book made Lady Mary posthumously famous.
Many editions followed in the eighteenth and nineteenth centuries. Lord Byron was a fervent admirer, and the letters were one of the chief inspirations of his book-length narrative poem Don Juan (1819-24). Subsequent editions of the Embassy Letters added more letters and correspondents, until in the mid-1960s Robert Halsband edited a scholarly edition of The Complete Letters (Oxford University Press, 1965-67). But it's remarkable to think that without the unauthorized actions of Sowden and the travellers who pirated her manuscript, we would likely know very little today about Lady Mary's extraordinary life and writings.
Last time: "Friends and lovers"
- Quoted in Isobel Grundy, Lady Mary Wortley Montagu, Oxford University Press, 1999, p. 40.
- Lady Mary Wortley Montagu, To Edward Wortley Montagu, October 1712, Selected Letters, edited by Isobel Grundy, Penguin, 1997, pp. 98-99; Montagu, Letter to Edward Wortley Montagu, 23 August 1713, Selected Letters, p. 110.
- Joseph Spence, Observations, Anecdotes, and Characters of Books and Men, Collected in Conversation, Vol. 1, edited by James M. Osborn, Oxford University Press, 1966, No. 765, p. 312.
- Montagu, To Francesco Algarotti, August 1736, Selected Letters, p. 226.
- Montagu, To Francesco Algarotti, 10 September, Selected Letters, pp. 227-228.
- Francesco Algarotti, Sir Isaac Newton's theory of light and colours, and his principle of attraction, made familiar to the ladies in several Entertainments, Vol. 2, translated by Elizabeth Carter, London, 1742, p. 14.
- Isobel Grundy, The Verse of Lady Mary Wortley Montagu: A Critical Edition, Vol. 2, Doctoral thesis, Oxford University, 1971, p. 598.
- Montagu, To Francesco Algarotti, 16 July 1739, Selected Letters, p. 245.
- Montagu, To Francesco Algarotti, ?May 1741, Selected Letters, p.285-286.
- Grundy, Lady Mary Wortley Montagu, p. 438.
- Montagu, Selected Letters, note p. 454.
- Montagu, To Francesco Algarotti, 12 March 1757, Selected Letters, pp. 436-437.
- Montagu, To Sir James and Lady Frances Steuart, 20 November 1761, p. 495.
- Grundy, Lady Mary Wortley Montagu, p. 623.
- Grundy, Lady Mary Wortley Montagu, p. xviii; Montagu, To Sir James Steuart, 12 April 1761, Selected Letters, p. 490.
- Quoted in Grundy, Lady Mary Wortley Montagu, p. 624.