Origin of the name Marshak

The name Marshak is an abbreviation of "Morejnu ha-Rav Shmuel Koidanover". This was the name of the once famous rabbi from Koidanov near Minsk who lived there in the 17-th century. To the best of our knowledge, all researchers of the Jewish genealogy agree with this version of the family origin.
The full name of the famous talmudist from Koidanov was Aaron Shmuel ben Israel Koidanover. He was born in 1614 and died in 1676. The abbreviation has three most spread ways of writing - Marshak, Maharshak and Magarshak. Apparently the difference in writing comes from writing or omitting "h" in the abbreviation "Morejnu ha-Rav Shmuel Koidanover".
In particular in the USA several families live whose family name is written as Magarshak. In Russia all people with this name (and they are all undoubtedly relatives) resided in Belorussia, in Koidanovo and Vitebsk. By the way the family of the famous poet and translator Samuil Yakovlevich Marshak, his brother Ilya and sister Liya, comes from there. Members of this family also lived in Minsk, Berdichev, Kiev, Vilno and Igumen.