Sonnichsen family members represented in the collection include Nicolai, Nicholas and his wife and son Albert (1878-1931).
Nicolai was Danish consul at San Francisco from 1874 to 1880. Nicholas fought with the Confederate Army, was imprisoned at Rock Island, Illinois, and after the war worked as a bookkeeper in San Francisco. Albert joined the U.S. Navy and was held captive by the Filipinos during the Philippine-American War (1899), took part in the Macedonian separatist movement against Turkey, and published books about his experiences.
From the description of Sonnichsen family papers, 1874-1919. (New York Public Library). WorldCat record id: 122532733