Researching my family name and not come across too many in Poland. My fathers family were from the Gerwiaty/Oszmiana area of what was Poland (pre 1939) and now Belarus.
My Grandfather was in the Polish army and as a result, his family were deported to Siberia and eventually onto the UK where they settled.
Although I can't prove it, it would seem that many Sys's stayed and moved to Lithuania. In fact, my Grandmother always called the family "Litwi" i.e. Lithuanians.
I had a email from a Sys in Lithuania and his family originates from the same village and mentioned one of their ancestors came from Sweden.
The oldest ancestor I found was a Ludwik Sys and it would appear that forename reappears in the Lithuanian's family tree, so I suspect a link.
Any information would be gratefully received as at Ludwik, I'm stuck - no proof of brothers, father or a definitive answer on sons!