Signed as brother-in-law of Maria de Meij when she bought a house on the Oosteinde

Maria de Meij bought the house that is now Oosteinde 252 from Aeltge Joosten, only daughter of Joost Jansz van Cortrijck, a clothing maker. Aeltge's husband Willem van Apperlo signed for her and Leeuwenhoek as brother-in-law signed along with Maria de Meij.

The notary document recording the sale says that the house was to the south of the porcelain factory the Lampetkan and north of the property owned by Gerrit Heinrixs van Raddich, an antique turner (made turned objects in an antique style). The following May, Leeuwenhoek and his wife Barbara inherited the house to the south of Raddich from Maria and Barbara de Meij's father Elias de Meij.