Conversation so far:
Who did Harriet Tubman marry?
Harriet Tubman married a free black man named John Tubman.
When did Harriet Tubman and John Tubman marry?
Around 1844, Harriet Tubman married a free black man named John Tubman.
Did Harriet Tubman and John Tubman have any kids?
Harriet Tubman adopted a baby girl named Gertie in 1874, and lived together as a family
Where did Harriet Tubman and John Tubman live?
John and Harriet Tubman lived in Maryland.

Question: What else is significant?
Self-contained rewrite: What else is significant regarding Harriet and John Tubman's marriage?