Sallie Casey Thayer was born on February 14, 1856 in Covington, Kentucky. She was married to William Thayer in 1880 in Kansas, where he was involved with the dry goods industry. William Jr, their only son, was born in 1882. Mrs. Thayer had a great appreciation for art and built a large collection during her lifetime. It was due to her passion for art that she made efforts to establish a more prominent art scene in the Kansas City area. She made the decision to use her own home as a gallery after several unsuccessful attempts to display her collection at local museums, because of limited space available at the museums. Her collection consisted of items acquired from the United States and abroad, and was eventually given by deed to the University of Kansas in 1917. Her collection was not displayed to the public until 1924 when Watson Library replaced Spooner Library, which then became the Spooner Thayer Museum of Art. Mrs. Thayer passed away on September 10, 1925.