The marker you've found commemorates Gideon Aughinbaugh, a significant figure in the early history of Alameda, California. He was a co-purchaser and co-founder of the city, meaning he played a direct role in acquiring and developing the land that would become the city of Alameda. The marker specifically highlights that he died at this location on July 7, 1897. This type of plaque, dedicated by the Alameda Historical Society, serves as a permanent memorial to important historical figures and events, often placed directly at the sites where they occurred.