Sansa Arryn was the Lady of Harrenhal, and is the mother of Petyr, Emmon, and Alicent Baelish.
History
Sansa was wed to Robert Baelish at a young age, and gave him three children. She was thought dead shortly after Petyr Baelish's death but was later revealed to be under the protection of Walder Bracken.
Fifth Era
Before the wedding of Alicent Baelish and Brynden Frey, Sansa was reunited with her daughter.