Tyler Arboretum, one of the oldest and largest arboreta in the northeastern United States, is a 650-acre public garden in Media, Delaware County, Pennsylvania. It was established in 1944 through a bequest of Laura Hoopes Tyler, a descendent of the property's original owner, Thomas Minshall. The Minshall family grounds became an arboretum in the early 19th century when brothers Minshall and Jacob Painter began amassing a collection of over 1,000 ornamental plants for scientific study. The Arboretum has approximately 18 linear feet of archival materials dating from 1681 to the present, which include personal and financial papers from the Tyler, Painter, and Minshall families who lived on the property for eight generations, as well as administrative records, correspondence, financial papers, historical research, and other materials relating to Tyler Arboretum. Of interest are a 1681 William Penn deed to Thomas Minshall, several 19th century family photograph albums, and the files of Dr. John Caspar Wister (1887-1982), who was the first director of Tyler Arboretum from 1946 to 1968 and is considered to be one of the premier horticulturalists of the 20th century. Today, Tyler Arboretum's mission is to preserve, develop, and share its diverse horticultural, historic, and natural site resources in order to stimulate stewardship and an understanding of our living world.