Conversation so far:
What happened to them?
Goodman notes that during this period in Russia, Jews had two basic alternatives for joining the art world.
What leads them their?
other alternative--the one that Chagall chose--was "to cherish and publicly express one's Jewish roots.

Question: What did this lead them to do?
Self-contained rewrite: What lead Marc Chagall "to cherish and publicly express one's Jewish Roots?"