Conversation so far:
when was the final appearance of Lucy Stone?
Lucy Stone went with her daughter to Chicago in May 1893 and gave her last public speeches at the World's Congress of Representative Women
where was the final appearance of Lucy Stone?
The World's Congress of Representative Women was a week-long convention for the voicing of women's concerns, held within the World's Columbian Exposition (Chicago World's Fair) in May 1893.

Question: what was the reason for the congress?
Self-contained rewrite: what was the reason for The World's Congress of Representative Women in May 1893?