The city at this time was multi-cultural: Mascov's family was prominent in the German speaking merchant community, his grandparents having fled to Danzig from the west during the Thirty Years' War.
By this time Mascov had already, during the course of his travels, visited the prestigious University of Harderwijk, and in an ingratiating letter dated July 1728 he received an offer to take a law professorship there, backed up by a stipend of 700 florins.
His time at Harderwijk was a success: the institution flourished and it is reported that he succeeded in attracting some of the best brains to the "Guelders Academy" (as it was also known) from the German and English nobility.
His colleague Georg Christian Gebauer [de] emerged with a badly scratched face, and a disciplinary enquiry against Mascov ended up condemning his intemperate conduct and dismissing him from his post.
His academic research was characterised by thoroughness and precision ("scribebat non multa – sed multum"); he knew how to express his thoughts with well chosen words and in lucid style, as a result of which he was esteemed by contemporaries as a leading exponent of "elegant jurisprudence" ("als eleganter Civilist"[1]) Even as a youth he became accustomed to an independent lifestyle, and while he was not opposed to women, he remained unmarried because he feared quarrels and domestic power struggles.