In Zutot vol. 3 I discussed a manuscript that contained the oldest known copy of the unpublished Hebrew grammar by Menasseh ben Israel. An eighteenth-century Portuguese owner of this manuscript noted that it had been copied by one Jacob Jesurun around 1655–1660. The manuscript remained in the possession of the Jesurun family until 1811, when it was auctioned. Apart from the name of the scribe who copied the manuscript, there is another indication that the Portuguese-Jewish Jesurun family was on good terms with Menasseh. This clue has everything to do with Menasseh’s portrait.
A.K. Offenberg, ‘A mid-seventeenth-century manuscript of the (unpublished) Hebrew grammars of Menasseh ben Israel and Isaac Aboab da Fonseca recovered,’Zutot. Perspectives on Jewish Culture3 (2004) 98–107.