Rev. Charles Montgomery Livingston was Isabella's brother-in-law. He married Marcia Macdonald in 1855 and little Belle was a part of their wedding day!
Early in their marriage, Charles was a professor at Oneida Seminary in New York. He was also in charge of the Young Men's Hall. Marcia's sister, Isabella, was a student there at the time. It was during their time at Oneida that Charles brought a student home for dinner—G. R. Alden! He would soon become a regular guest and later became a member of the family when he married Isabella.
In "Memories of Yesterdays," Isabella recalls that in those years Charles "was a dear to me as though he were my very own brother...no own brother could have been more kind and helpful than he was, not only in my studies but in other ways that influenced all my future life."
Later, as a Presbyterian and Congregational minister and home missionary, he and Marcia served congregations in several states. A serious throat condition often required rest from preaching, so the family never stayed more than a few years in one church. Delving into church records, you can see that the Livingstons were much loved by those whom they served.
Rev. Livingston contributed to two books that were family efforts, A Sevenfold Trouble and The Kaleidoscope, but he was also a regular contributor to The Pansy, a children's magazine that sister-in-law Isabella edited. He shows up as C.M.L. or Uncle Charles, and he often introduced new inventions such as Thomas Edison's phonograph. He actually encouraged readers to write Mr. Edison so that they might learn more about the fantastic invention.
Charles was called home in 1900 at age 71 and Marcia went to live with her daughter, Grace, who was also recently widowed. If you look carefully, he lives on among the characters in Grace Livingston Hill's books.