With which person did Elizabeth Cady Stanton form a 50-year friendship and partnership to work for women's rights?

Elizabeth Cady Stanton formed the friendship with Susan B. Anthony.

Susan B. Anthony was an American social reformer and women's rights activist. She played an important role in the women's suffrage movement and she appeared before every Congress between 1869 and 1906 on behalf of women's suffrage.

In 1851 she met Elisabeth Cady Stanton during an anti-slavery meeting in Seneca Falls. There, their historic and long-lasting friendship began.

They became co-workers in social reform activities and together they founded the New York Women's State Temperance Society and later the Women's Loyal National League that fought a long battle to abolish slavery.

Their biggest achievements were, however, associated with work for the American Women's Suffrage Association.

Stanton and Anthony remained close friends for over 50 years.