I am researching the last name "Jena" of my maternal Great Grandfather.  He immigrated from Ritschenwalde, Prussia [ Noe Ryczywo'l Poland].  There doesn't seem 
to be any records there of a Jena family earlier than about 1840s.  The only other Jena families that I could located were from Detmold, in Germany, but some of the last names were Jena and others were Michaelis Jena.  Does anyone have any thoughts on why some people would have just Jena and others Michaelis Jena in the same family?

    For example
                   LC3Z-2JK 

 Lew Meixler

My GtGt Grandmother was Henriette Michaelis-Jena b. Detmold 1820 m Israel Heinemann Heimann 1842 and d 1850 in Luegde after giving birth to four children.
A generation back and several sibs were Michaelis, one Michaelis-Badt and Henriette's father Michaelis-Jena One more generation back and one brother is Jena and the other Michaelis!
I have a note but don't remember from where - that it was a way of distinguishing different branches of the family and is mentioned in histories of Westphalia.
There is a similar pattern in my Heimann family from Luegde where brothers take different surnames.

Jena is a town in Thuringia to which I have not come across a connection.

As we clearly both descend from Joseph MJ and Brendel Gerso. Treuenfels , I should be most interested to know more about the Ritschenwalde connection.

Hazel Dakers, London UK researching