described butter as a medicinal agent only. Middle Ages In the cooler climates of northern Europe, people could store butter longer before it spoiled. Scandinavia has the oldest tradition in Europe of butter export trade, dating at least to the 12th century. After the fall of Rome and through much of the Middle Ages, butter was a common food across most of Europe—but had a low reputation, and so was consumed principally by peasants. Butter slowly became more accepted by the upper class, notably when the Roman Catholic Church allowed its consumption during Lent from the early 16th century. Bread and butter became common fare among the middle class and the English, in particular, gained a reputation for their liberal use of melted butter as a sauce with meat and vegetables. In antiquity, butter was used for fuel in lamps, as a substitute for oil. The Butter Tower of Rouen Cathedral was erected in the early 16th century when Archbishop Georges d'Amboise authorized the burning of butter during Lent, instead of oil, which was scarce at the time. Across northern Europe, butter was sometimes packed into barrels (firkins) and buried in peat bogs, perhaps for years. Such "bog butter" would develop a strong flavor as it aged, but remain edible, in large part because of the cool, airless, antiseptic and acidic environment of a peat bog. Firkins of such buried butter are a common archaeological find in Ireland; the National Museum of Ireland – Archaeology has some containing "a grayish cheese-like substance, partially hardened, not much like butter, and quite free from putrefaction." The practice was most common in Ireland in the 11th–14th centuries; it ended entirely before the 19th century. Industrialization Until the 19th century, the vast majority of butter was made by hand, on farms. Butter also provided extra income to farm families. They used wood presses with carved decoration to press butter into pucks or small bricks to sell at nearby markets or general stores. The decoration identified the farm that produced the butter. This practice continued until production was mechanized and butter was produced in less decorative stick form. Like Ireland, France became well known for its butter, particularly in Normandy and Brittany. Butter consumption in London in the mid 1840s was estimated at 15,357 tons annually. The first butter factories appeared in the United States in the early 1860s, after the successful introduction of cheese