Catharina Philips Leeuwenhoek
When she married at age 18, Antony's youngest sister Catharina lived on Verwersdijk, probably in the house of her cousin Geertruijt Huijchs. Her brother Antony used the same address when he married the previous summer.
Catharina's husband Claes Jans lived on Choorstraat. They moved from Delft to Rotterdam, where he was an auctioneer. Over the next twenty years she bore eleven children, fewer than half of whom survived childhood. Claes van Leeuwen is listed as owner of A0557 now Zuideinde on the west bank of the Schie about a quarter of a mile south of Delft's Rotterdam gate. He died before 1676, when Leeuwenhoek calls his sister a widow in a letter to Oldenburg.
According to his letters, Antony visited his sister in Rotterdam. In 1676, he had issues of Philosophical Transactions sent to Catharina's house in Rotterdam because they would get to him sooner. As packages, they got to the Dutch Republic with the letters from England. However, the letters then got to Delft sooner than the packages. It was quicker for Catharina to take them to Delft or give them to someone going that way. Leeuwenhoek gave her address:
Juffr Catatarina Leeuwenhoeck
Wede van Sar. Claes van Leeuwen
op de Hoogh-straet in het Oude
Gemeenlants Huijs. Tot Rotterdam.
The Wede in the second line stands for widow and the Sar. is an abbreviation for the redundant saliger, deceased.
The following year, 1677, Catharina was back in Delft. She had a twenty-year-old daughter and five younger children between twelve and one.
She is listed in the Delft treasurer's accounts and in other records as collecter of the excise tax on auctioned buildings (boelhuijsen) from 1677 through 1691. She began paying the city 1,700 guilders. On July 2, 1685, the mayors met and appointed Catarina to a three-year term. Also, her payment rose to 2,000 guilders. From 1689 to 1691, she served a second and final three-year term for the same 2,000 guilders. By then, her children were grown. There is no record that she remarried.
On September 17, 1683, in a letter (AB/CL 76) to Francis Aston, "I am looking forward to the Transactions mentioned in your last letter; please send them to Rotterdam, bearing this direction: To Mrs. Catharina Leeuwenhoek, Hoogh-straat int Oude Gemenelants huis At Rotterdam". Did his sister keep a residence in Rotterdam while she was a tax collector in Delft?
In 1684 as a widow, Catharina received 631 g from estate of great uncle Johan Sebastiaans van den Berch.
On December 8, 1693 (AB/CL 128), Leeuwenhoek asked Richard Waller to send parcels of Philosophical Transactions, not through Amsterdam, but "to address the same to Mr. Philip van Leeuwen at Rotterdam, who is my sister's son and who, with every Convoy that goes to London or comes back from there, always ships goods to London or receives them."
In February 1697, in his first letter (AB/CL 182) to Hans Sloane, the newly appointed editor of Philosophical Transactions, Leeuwenhoek asked Sloan to send copies to Mr. Philip van Leeuwen, "living in the Hoogstraat in the Mee Balen at Rotterdam." Philip was Catharina's 30-year-old son, and he must have been living in the family home on the Hoogstraat.
The Collected Letters says that Catharina lived until 1708, though I can't find any record of her activities after 1691, when she was 54.
After his daughter Maria's lion's share, Antony bequeathed most of the rest of his estate to sister Catharina's children and grandchildren.