Her father, Yosef Feigenbaum, was killed in the Holocaust; her mother, Ella (née Fabian), survived by escaping a train that was taking her to an extermination camp and joined the Polish resistance.
During this time Jacoby, baptized and renamed Barbara, lived hidden in the home of a Polish woman.
After the war, she was reunited with her mother; from 1945 to 1949, they wandered through Poland, Germany, Italy, and South America.
[1] Using an 18th-century drawing by Elzear Horn, Jacoby was able to suggest a reconstruction of the tomb of King Baldwin V of Jerusalem, which had been destroyed in 1808.
Her family donated the fruit of her research, a collection of photographs of Crusader sculpture in Israel, to the Younes and Soraya Nazarian Library, which preserved it and made it accessible to the public.