The Soesan family is a Jewish family, of which the geographical roots are very obscure. The oldest ancestor, David Schuschan (1660?-1724), who settled in Amsterdam, is said to have come from the city of Shush in Persia (= the biblical/historical Susa). However, these claims lack sources to support them. The Persian origin story seems even more unlikely, when considering the fact that there is absolutely no documentation of Persian Jews migrating to the Dutch Republic in the early modern period.
The earliest Schuschan/Soesan coming from Germany or Eastern Europe (and thus being Ashkenazi) is a more plausible theory. The fact that David's children and grandchildren all had marriages with Jews of Ashkenazi origin suggests that he was as well. Right from the creation of the first major Jewish communities in the Netherlands (mainly in Amsterdam) in the late 16th/early 17th century there was a clear dividing line between the Ashkenazim and Sephardim. The Soesan family was accepted into the Ashkenazi community, which implements that the family was familiar with Ashkenazi culture.
At one point in time the name Schuschan changes to 'Soesan', 'Susan', 'Sousan' and 'Sousa'. The variant 'Suesan' is likely the result of a misreading by a civil servant.
Feel free to add any profile with the surname Soesan, or one of the variants.