Anna Craig was elderly woman and member of the congregation of the town of Walnut Grove.
After a time, she falls in love with the Reverend Alden and tells it to him in a private meeting at her house apparently on a matter of faith. At first, Reverend Alden took it as a expression of Christian love not a personal romantic interest between a man and a woman and panicked and quickly withdrew. She and Reverend Alden had a wedding planned until the local Church congregation intervened and called a meeting on the matter. (Episode 606: The Preacher Takes A Wife)