Genealogy /
I am 1/8 Polish on my mother's side - not Polish enough / Lithuania and Zmudz in Poland's ancestry [110]
I thought much about ethnic Lithanian people in Lithanian Szlachta.
I came to the conclusion that even at the beginning of 15 century despite the fact many of them could speak Lithuanian in their families, the majority already received Slav surnames. The surnames of szlachta appeared during the creation of lists of militia (so called Popis). In Litwa they were all composed in Russian. The surname as rule was formed by father's name according to Russian standarts. If an ethnic Lithuanian had a father by the name of Pawel he became Pawlowicz and not Pavlauskas as today.
Sometimes we can suspect (only suspect) an ethnic Lithanian origin. When the surname derives drom a name that Orthodox people don't have. For example Franckiewicz or Stankewicz. The majority of ethnic Lithuanians were Roman Catholics and very few Rusins in Litwa of 16 century
Witek
Did you notice any movement toward polonization of surnames in Lithuania in 17 century?
I know notning about that but some facts make me suspect that.
For example in the list of militia in Litwa in 1519 some 95% of Lithanian szlachta surnames have suffix -wicz and there are only very few surnames with suffix -ski.
As to 18 century, I think some 50% of surnames had suffix -ski.
We can suppose the majority of surnames with suffix -ski may appear in late 16-17 centuries when szlachta nubber was multiplicated in Litwa and new families with new surnames (already polonized) appeared. Besides that many old Lithanian families-clans separated in 16-17 centuries into different new families that received new surnames.
But there are still doubts...
For example in the List of militia of 1519 only one family with Rusin surname Anisimowicz was mentioned and the family was from Wolkowysk (sorry for possible wrong spelling). There were no Anisimowicz in 18 century as far as I know, but family Onichimowski was well known in Wolkowysk powiat in 18 century.