The question is:
"The first name Alexander (usually in the Yiddish form of Sender,
after Alexander the Great, is not an uncommon Jewish first name.
Alexander lived in the 4th century BCE, before the division in the
Jewish world between Ashkenazim and Sephardim, yet, as far as I
know the name is only used by Ashkenazim. Can anyone explain this?"
Alexander was often a name used to refer to the 'good Czar' Alexander,
who was assassinated n 1881. That is why 1881 is the date of the
start of the big increase in Jewish emigration >from Russia. Alexander
was much kinder to the Jews than those before or after him-but was
not what we would call kind.