Chocolate was once drunk as a bitter, chilli-spiced liquid

For most of its 3,000-year history, chocolate was consumed as a cold, frothy, bitter drink. Mesoamerican civilisations — Olmec, Maya, and Aztec — ground cacao beans and mixed them with water, chilli, and spices. The drink was associated with royalty and ritual; Aztec emperor Montezuma reportedly drank 50 cups a day. When chocolate arrived in Europe in the 16th century, sugar was added and it was served hot. Solid chocolate bars weren't developed until 1847, when Joseph Fry's company found a way to combine cocoa butter, cocoa powder, and sugar into a mouldable solid.

Source: Coe & Coe, The True History of Chocolate (1996)