Raisins and citron were the two most commonly used dried fruits in election cakes, but I like to use equal amounts of a large variety of fruit, such as dried sour cherries, blueberries, citron, and dark and golden raisins.

NPR: Two Centuries of 'Baking in America'

Citrus bergamia, as it's known in botanical circles, first showed up 300 years ago in Southern Italy, the result of crossbreeding a sour orange with "something else, " variously identified as a citron, a lemon, a lime or a Palestine sweet lime.

WSJ: Bergamot Is No Lemon