It had been a year, he recalled, since he had met Beeckman.

He had been walking through the streets of Breda when he came upon a poster advertising a local mathematician's open challenge to solve a certain problem. 

Since it was in Dutch--a language he then could not read--he asked another individual nearby to translate the invitation into French or Latin. The man, an Isaac Beekman, explained the problem in Latin and gave him his card. (His translator, he learned, had recently received his doctorate in medicine.) The next day, he called upon his new acquaintance in order to share the answer he had derived to the problem.

They became almost at once good friends, and would talk into the night about the laws of falling bodies, the possibility of magic, the nature of music. He had written, he remembered with some embarrassment, a treatise on music in Latin as a Christmas present for him.