The Caile-Bayly house, one of the oldest buildings in Cambridge, was built sometime in the mid-18th century. Archaeology and architectural analysis indicate that the one-room cabin behind the house first appears to have served as an office or kitchen, was moved to its current location in the mid-19th century, and later, as suggested by late 19th century artifacts, served as a home for at least some period of time. Because outbuildings associated with enslaved workers often had multiple functions, the cabin may also have been used as seasonal or temporary sleeping quarters during the mid-19th century. On October 17, 1857, Lizzie Amby, a woman enslaved by Dr. Alexander Bayly, left the Bayly House with her husband, Nat, and fled with 13 others from Cambridge. They traveled north on the Underground Railroad, using safe houses where they rested and gathered supplies and money. At one stop, when an abolitionist asked Nat whether Lizzie would fight for her freedom, he replied, "I have heard her say he would wade through blood and tears for her freedom." Their safe arrival in New York is known from a letter Nat wrote to his mother in Baltimore on June 10, 1858, saying they were doing well. After Lizzie escaped, Alexander Bayly placed an advertisement in the local Democrat newspaper on October 19, 1857, offering for her return.