François de Bassompierre was born in 1579 into an aristocratic family at the Château de Haroué in Lorraine (now France). He was educated with his brothers in Bavaria and Italy, and, in 1598, was introduced to the court of King Henry IV of France, where he became a favourite of the king. As a young man, he was involved in various military campaigns: in Savoy in 1600, and in Hungary in 1603 against the Turks. He assisted Marie de’ Medici, queen mother, against the nobles in 1620, and helped the king against Huguenot risings (for which he was made a Marshal of France), and during the siege of La Rochelle in 1628. He was sent to raise troops in Switzerland when Louis XIII marched against Savoy in 1629.
Bassompierre also served, at various times, as a diplomat. In 1621, he went to Madrid to settle a dispute concerning the seizure of the Valtelline forts by Spain. In 1625, he was dispatched to Switzerland, and a year later to London, to secure the retention of the Catholic ecclesiastics and attendants of Henrietta Maria, wife of King Charles I of England. Bassompierre was secretly married to Louise Marguerite, widow of François, prince de Conti, and friend of Marie de’ Medici. She bore him one son (but he also had another, illegitimate son). Louise Marguerite’s hostility to Cardinal Richelieu, however, led to Bassompierre being imprisoned from 1631 until after Richelieu’s death in 1643. Although his status was restored, he died a few years later, on 12 October 1646. Wikipedia and Encyclopaedia Britannica have, more or less, the same biographical information, both drawn from the out-of-copyright 1911 edition of Encyclopædia Britannica.
Bassompierre is largely remembered because he left behind a memoir of his life, first published in Cologne in 1665, but many times since then - see Internet Archive. He also published diary accounts of his diplomatic missions to Spain, Switzerland and England, but only the latter has been published in English (John Murray, 1819, translated by John Wilson Croker) - as Memoirs of the Embassy of the Marshal de Bassompierre to the Court of England in 1626. This, too, is freely available at Internet Archive. Here are several extracts.
15 October 1626
‘Thursday the 15th, on which the Earl of Britswater came with the king’s coaches to fetch me to Hampton Court; then the duke shewed me into a gallery, where the king was waiting for me, who gave me a long audience and well disputed. He put himself into a great passion, and I, without losing my respect to him, replied to him in such wise, that, at last, yielding him something, he conceded a great deal to me. I witnessed there an instance of great boldness, not to say impudence, of the Duke of Boukinkam, which was, that when he saw us the most warmed, he ran up suddenly and threw himself between the king and me, saying, “I am come to keep the peace between you two.” Upon which I took off my hat, and as long as he staid with us I would not put it on again, notwithstanding all the intreaties of the king and of himself to do so; but when he went I put it on without the king’s desiring me. When I had done, and that the duke could speak to me, he asked me why I would not put on my hat while he was by, and that I did so, so freely, when he was gone. I answered that I had done it to do him honour, because he was not covered and that I should have been, which I could not suffer; for which he was much pleased with me, and often mentioned it in my praise. But I had also another reason for doing so, which was, that it was no longer an audience, but a private conversation, since he had interrupted us, by coming in, as a third, upon us. After my last audience was over, the king brought me through several galleries to the queen’s apartments, where he left me, and I her, after a long conversation; and I was brought back to London by the same Earl of Britswater.’
16 October 1626
‘Friday, the 16th, I was to see the Earl of Holland sick at Inhimthort. The king and queen returned to London. M. de Soubise came to see me. Afterwards the duke sent to beg of me to come to Sommerset, where we were more than two hours disputing about our business.’
17 October 1626
‘Saturday, the 17th, I went to make my bow to the queen at Withal, and to give her an account of my conference of the day before with the duke.’
18 October 1626
‘Sunday the 18th. I was visited by the secretary, Couvai, who came to speak to me from the king.’
20 October 1626
‘Tuesday, 20. Viscount Hamelton (Wenbleton) and Goring came to dine with me. After dinner I was heard at the council, and on my return the Venetian ambassador came to visit me.’
21 October 1626
‘Wednesday, 21st. I wrote a despatch to the King (of France). I was to see the queen, and afterwards to confer with the duke in Sommerset (House).’
22 October 1626
‘Thursday, 22d. I was in the morning to see the ambassador of Danemark. The duke, with the Earls of Carlile and Holland and Montaigne, came to dine with me; I saw, en passant, the ambassador of the States on business, then I was to the queen’s, and that evening at Madame D’Estranges.’
23 October 1626
‘Friday, 23d. I was to see the Earl of Carlile and the Venetian ambassador.’
24 October 1626
‘Saturday, 24th. I was to see the queen where the king came, with whom she pick’d a quarrel. The king took me to his chamber, and talked a great deal with me, making me complaints of the queen, his wife.’
25 October 1626
‘Sunday, 25. The Earls of Pembrac and Montgomery came to see me, then I went for the duke, whom I took to the queen’s, who made his peace with her; which I had brought about with infinite trouble. The king came in afterwards, and he also was reconciled with her, and caressed her very much - thanked me for having reconciled the duke and his wife - then took me to his chamber, where he showed me his jewels, which are very fine.’
26 October 1626
‘Monday, 26th. I was, in the morning to see the ambassador of Danemark; after dinner I went to the queen at Sommerset, and fell out with her.’
27 October 1626
‘Tuesday, 27th. The Duke, the Earls of Dorset, Carlile, Holland, Montaigu, and Goring, came to dine with me. I went afterwards to see the Earl of Pembroc and Carleton. In the evening I had a courrier from France.’
28 October 1626
‘Wednesday, 28th. I was at Withal in the morning to speak with the duke and Secretary Couvai, because the king was going to Hampton-Court. After dinner I went to see the queen at Sommerset, with whom I made it up. In the evening the duke and Earl of Holland took me to sup at Antonio Porter’s, who was entertaining Dom Augustin Fiesco, Marquis of Piennes, the Chevallier de Jars, and Gabellin. After supper we had music.’
29 October 1626
‘Thursday, 29th. In the morning I had visits from the Earl of Holland and the Earl of Carlile. After dinner I went to see the ambassador of Holland.’
30 October 1626
‘Friday, the 30th. I was to see the queen at Sommerset, and the duke at Valinfort. The resident of the king of Bohemia came to sup with me.’
31 October 1626
‘Saturday, last day of October. The ambassador of Danemark came to see me, and afterwards I came to see Madame D’Etrange.’
1 November 1626
‘Sunday, the 1st of November, and All Saints Day. I performed my devotions, and afterwards was to see the Duchess of Lennox and Secretary Couvai. A council was held to-day for my business.’