About family Shagal

When I was 5 years old, my mom told me I was a descendant of a read headed Jewish king. I thought she was kidding. 30 years later I was doing research on our family name and came across an article written by someone with no relation to our family. the write went on to say that Sagan (Seagal, and ultimately Shagal) was an honorary religious Levite title given to the royal family of Khazars. The last name means Assistant to the High Priest. Upon reading this I called my dad, and asked if we were posibly descendants of royalty? To which my dad replied- "Your gradfather has been saying we are the descendants of Jewish Aristocracy his whole life" (in those words exactly). The only history I have heard about my great grandparents is that they had to flee from Belarus because the communists were killing the wealthy. Our family were wealthy land owners (I believe they also owned a grain mill). My great grandfather was a businessman, but our families traditional profession was Kosher butchers. Great grandfather Alter was not religious, but his dad was. I have seen my grandthaer, Semyon hold up an article of a cousine/uncle (not sure the exact relation) of Mark Shagal, the painter. so I know we are related and not far removed from him.