According to Jane Fonda in her autobiograpy (referenced below), the Fondas "...were originally from a valley in the Apennines, about twelve miles outside Genoa, Italy." The name Fonda ("bottom") came from their geographic positioning at the bottom of the valley. A 14th Century ancestor was the Marquis de Fonda of the Republic of Genoa, who was banished to Amsterdam after "being branded a traitor to his class" when he tried to overturn the aristocratic government. His descendant Jellis Douw was the first Fonda to immigrate to America in the mid-1600s, a member of the Dutch Reform Church fleeing religious persecution. (pg 29-30).
LITERATURE:
"My Life So Far" Jane Seymour Fonda, Random House, NY 2005