14th the Aztec Empire liked to drink cocoa so cacao beans became a form of currency. All Aztecs that grew cacao beans were ordered to pay them as a tax.
16th Spaniards would use it as a medicine to treat illnesses.
17th Century chocolate was "fashionable" in Europe for the few.
18th Someone made the first chocolate bar.
19th Chocolate underwent a transformation from a primarily drink to a food. 
20th Chocolate got Rad!