(Cambridge, 1934), p. 64.</ref> During this period he used his influence to promote the marriage of the queen with the Duke of Alençon, with a view especially to strengthen and maintain the alliance of the two countries. But Elizabeth made so many promises only to break them that at last he refused to accept them or communicate them to his government. The Italian philosopher Giordano Bruno was a member of the Castelnau household in London for two years. Bruno dedicated three dialogues on the infinite nature of the universe to Castelnau. A suggestion that Bruno leaked confidential information from the embassy in this period, proposed by the historian John Bossy, has not gained much acceptance. The Italian writer and linguist John Florio worked for Castelnau between 1583 and 1585. Florio was also his daughter's tutor. Castelnau's wife Marie had difficult pregnancies and miscarriages and she crossed and recrossed the English channel to see physicians in France, at great expense. Mary, Queen of Scots, and letters in code In London, Castelnau de Mauvissière resided at Salisbury Court near Fleet Street or Butcher Row near the Strand. Mary, Queen of Scots, sent letters to him from captivity at Sheffield Manor and Castle. He presented her letters to Elizabeth I. Castelnau's wife, Marie, sent Mary clothes, and helped to find women to join her household. Mary called her "ma commère", meaning her namesake. What Mary wants Castelnau showed some of Mary's letters to William Fowler, and he informed Francis Walsingham. Mary had written that she was not Elizabeth's prisoner, but a captive of the Lord Treasurer, William Cecil. Mary wrote secret letters in cipher to Castelnau complaining of her bad treatment, in 1581 asking for French money, soldiers, and artillery to be supplied according to the traditional Auld Alliance between England and Scotland. In 1582, she hoped that Castelnau's negotiations would lead to her release. In the short term, she wanted Castelnau to obtain permission for visits to Buxton for her health. Mary's physician, Dominique Bourgoing, kept Castelnau informed of Mary's illnesses. Castelnau also interceded with Elizabeth I for delivery of clothes, letters, and preserves from France. Castelnau's letters kept Mary informed of events in France. Castelnau helped get a passport for Jean de Champhuon, sieur du Ruisseau, her Fremch chamberlain and a brother-in-law of Mary's secretary Claude Nau, so he could travel and help her in affairs. Ruisseau was a lawyer and