By the middle of the summer of 1661, Spinoza was living in Rijnsburg. He lodged with Herman Homan, a chemist-surgeon, in a house on the Katwijklaan, a quiet street removed from the center of the village. Homan belonged to the local “college,” and it was probably through his Amsterdam Collegiant friends that Spinoza was referred to his new landlord. The house is still there, its facade graced, since 1667 (after Spinoza's departure), with a stone bearing a Dutch inscription from a play by Dirk Camphuysen:

In the back of the house was a room where Spinoza set up his lense grinding equipment. It was a craft he must have begun working on while still in Amsterdam, for by the time he settled in Rijnsburg he was fairly skilled at it and ready to get to work. As early as fall 1661, he was known for making not just lenses but also telescopes and microscopes. Spinoza may initially have taken up the production of lenses and instruments to support himself. When he was forced to break off all relations with the Jewish community completely, and therefore could not conduct his importing business, he had to seek his living by other means.