Ida Nilsson (1840–1929), the youngest daughter of the famous scientist and archaeologist Sven Nilsson (1787–1883), accompanied her father to scientific meetings all over Europe. In 1869 the fourth Congress for Prehistoric Archaeology and Anthropology was held in Copenhagen. The Nilssons were of course invited. Ida told her close friend Anna Hierta about her experiences in a long letter. It was the first archaeological congress where she and other ladies were officially welcome. Ida’s long letter gives us invaluable information on how a young lady found herway in science. She writes about discussions with archaeologists, excursions, dinnersand speeches. Her letter is an invaluable source for the proceedings of the congress. There were several other ladies present at the congress. Somehow these brave ladies have been forgotten in the history of our discipline.