Visited by Francesco Cornaro
Francesco Cornaro or Corner was appointed the Venetian ambassador in London in 1703 but he did not arrive until late 1705. He stayed in The Hague from 4 September to 13 November while he waited for a favourable wind for the crossing to England. During that time, he visited Leeuwenhoek in Delft.
Leeuwenhoek addressed letter 260 to him on December 18, 1705. The orginal complete letter has not survived. In July 1707, Leeuwenhoek sent a copy of that letter to the Royal Society, and an extract about pearls was published shortly thereafter in Philosophical Transactions, vol. 25, no. 311 (July, August and September 1707).
Before that, however, Leeuwenhoek mentioned the visit in Letter 267 of 17 May 1707 to John Chamberlayne:
Now as the Bezoar Stone is of no use in physick so neither are pearls as I have writ at large to his Excellency Francisco Cornaro Envoy, from ye Republick of Venice to her Majesty of Great Brittain. This Gentleman did me the honour one afternoon to come to me and see my Observations wherein he took much pleasure. Understanding that I never wou'd accept of any gifts, he nevertheless before his departure took care to send me his coat of arms finely painted for which I made him my acknowledgmts. by a Letter into England and sent also his Excellency my Remarks about Pearls, viz. that they were of no use in physic, wherewth his Excellency was much satisfyed & thanked me by way of Answer.
Neither of Corner's letters to Leeuwenhoek has survived, the one probably from Den Haag in October 1705 with the coat of arms and the other probably from London in December, a thank-you for the letter of December 1705 about pearls.
Corner was elected a member of the Royal Society on November 30, 1708, and returned to Venica the following year.