A mirror for the present
When the War of Resistance against Japanese Aggression (1931-45) broke out, he traveled to Geneva to speak at the League of Nations, helping China to win international support.
Koo was ambassador to Britain from 1941 to 1946, during which time he promoted talks between China and Britain, a milestone in the process of abolishing unequal treaties Britain imposed on China.
He also contributed greatly to the founding of the United Nations at the end of World War II.
"Koo was one of the very few senior diplomats in the world who experienced both the forming of the League of Nations and the establishing of the United Nations," says Jin Guangyao, a Fudan University historian who has written a biography of Koo.
Jin studied Koo's archives when he was doing research in the US in 1997.
"Back then, I had to transcribe the papers," Jin recalls. "I'm sure the digital archive will benefit many researchers when it goes online."
From 1957 to 1967, Koo served as a judge at the International Court of Justice at The Hague.
After retirement he moved to New York, where he died in 1985. He was 97 years old.
He bequeathed to his alma mater, Columbia University, several hundred hours' worth of taped oral history and donated the paper documents that largely make up the archive.
Concluding his oral-history project in 1975, Koo wrote: "Since the early years of my career, I have always been keenly interested in preserving for future generations important diplomatic communications and references.
"For the history of today has its origin in yesterday, and such archives not only provide us with the mirror of the past, they also help us to better understand the changes taking place in our world."
Contact the writer at xingyi@chinadaily.com.cn