Gerard van Assendelft
Assendelft was the son of the Delft mayor and magistrate Adriaen van Assendelft to whom Leeuwenhoek wrote letters among his Send-Brieven.
Son Gerard began his studies at the University of Leiden in 1717, the same year as Willem van der Lely.
By 1720, he had returned to Delft, where he joined the civic guard and was a member of the De Confrérie van de Handbusch binnen Delft. In 1723, he was the city's shooting champion (schutterkoning).
His career eeems to have paralleled that of his brother-in-law Willem van der Lely, who early in his career served as secretary in some of Delft's outlying districts. In the same years, Assendelft was secretary of the baljuwschappen Hof van Delft, Vrijenban, Abtsregt, Biesland, Groeneveld, and ’t Woudt. Back in Delft, the was commissioner of marital records in 1722, rentmeester of the Oude Mannen - en Vrouwenhuis in 1727, and secretary of the Groote Visscherij in 1732, among other offices.
He was a member of the Delft Veertigraad from 1734 to 1739, which was odd. Those appointments were ordinarily made for life. During that time, he was harbormaster for Delfshaven from 1736 to 1738.
He couldn't have fallen too far out of favor, however, because he was appointed master of the orphanage in1739 and then secretary of the Weeskamer from 1739 until 1760. It was in that capacity that he accompanied his brother-in-law Willem van der Lely, notary, to make the inventory of Maria van Leeuwenhoek's house in 1747.
Assendelft lived near van der Lely on the Koornmarkt. The tax records from 1749 state that he employed two maids, a seamstress, and a servant.
GAD, Impost 1749