What is the theme in The Keepers of the House by Shirley Ann Grau?

The Keepers of the House utilizes very few specific dates. Based upon basic United States history, one can deduce that the characters were born as early as 1800 and that the most recent sections of the book are set in the mid-1900s. The reader learns that there were five generations of William Howlands, the first of which was approximately seventeen years old when he was discharged from the the American War of 1812 (which lasted until 1815). From a strictly mathematical perspective, the first William Howland was therefore most likely born in 1798. At that time in history, families were begun young and lifespans were shorter. Assuming a conservative thirty years for each generation, the main character, William Howland, would have lived during the 1900's, as would have his children, Abigail, Robert, Nina and Crissy. These deductions make sense when one factors in the politics of the time.