While Thomas Jefferson is often credited with inventing macaroni and cheese after he brought back a macaroni machine from a trip to Europe, he was not the first to come up with the idea, according to the Thomas Jefferson Foundation.
Macaroni derives from the Italian word "maccheroni," which at the time was a general term for pasta. What is believed to be the original recipe for macaroni baked with a cheese sauce can be found in the 14th century cookbook, "Liber de Coquina," which is thought to have been written by an Italian author, and is printed in full (in Latin), here.