Lillian Clark Weaver, was born in Forestville, Chautauqua County, New York, on April 19, 1873. She was the daughter of Prof. and Mrs. A. A. Weaver. Weaver was a graduate of the 1895 Class at Vassar College, Poughkeepsie. After her graduation from Vassar, she went to teach at a girls' school. She conducted a private school for girls in Andrebrook, Tarrytown-on-Hudson, NY. In 1914, she moved to Europe and opened the school in Munich, Germany. She was forced to close a short time later, due to the advent of World War I. After the war, she moved back to Europe and continued to teach.

Friedrich "Fritz" Bruckmann, was a photographer and art historian in Germany at the turn of the 20th century. He worked with rotogravure in his photography, buying the process from its creator in 1903. He loved the mountains, as can be read in his letters. He worked for Andrebrook School teaching photography, recording trips, and creating the image for their pamphlets.

Edna Ferber is mentioned in one of the letters. Ferber was born August 15, 1888, and died April 16, 1968. She was an American novelist, short story writer and playwright. She won the Pulitzer Prize forSo Big (1924), Show Boat (1926), and Giant (1952).

Miss Weaver's School started in Munich, later opened to New York in 1914. The Andrebrook (Andre Brook School/ Castle School) moved to Tarrytown in 1920. The Munich branch was reopened in 1930. Girls of high school age were offered special courses as well as college preparation. Lillian C. Weaver left Andrebrook for good on June 15, 1942.