Sponge cake is a light cake made with egg whites, flour and sugar, sometimes leavened with baking powder. Prior to the invention of baking powder, they were leavened entirely with beaten eggs, which distinguishes them from the family of yeasted cakes that were also popular in this time period.
Once baking powder became available in the mid-19th century, sponge cakes could be made with richer batters including butter, which led to richer variants including Genoise. In the 20th century, chiffon cake and angel food cake became popular variants of the basic sponge cake template.