About four centuries passed between the first appearance of pamphlets in which the medical uses of petroleum were discussed (for example, the Tegernsee (southern Bavaria, 1430), Geneva (Swiss Confederacy, 1480), Nurnberg (northern Bavaria, 1500), and the Antwerp (Duchy of Brabant, today Flanders, 1540-1550) pamphlets), and Michael Faraday's discovery in 1825 of the chemical composition of benzene derived from bituminous oil as a compound of carbon and hydrogen. During this long time span, studies of oil, carried out between alchemy and chemistry, benefited from rapid advances and brilliant insights, much as they had moments of stagnation, and disappointing regressions. In 1855 the chemist Benjamin Silliman Jr., of Yale University, proved that crude oil could be decomposed through a process of fractional distillation into a range of fuels and lubricants cheaper than the oils, greases and waxes rendered by animal fats and vegetal matter (Silliman 1855; Forbes 1948 Forbes 1958). In the course of the early 1860s, oil became the main source of illumination first in North America, then in Europe and Australia. This transformation of oil from a substance of limited use into a commodity of mass consumption radically changed the pattern of oil finding and production. Crude was no longer collected just from natural springs or draining seepages, but was pumped out of the ground from wells drilled by machines using steam power. This was the first step toward the modern oil industry, and a breakthrough in the history of energy: The beginning of an oil society. The first part of this article provides an introduction to the early uses and production of petroleum in Europe, and advances in understanding the nature, the physical properties, and the composition of hydrocarbons. It provides a brief analysis of the interaction between technology, society and the environmental context in northwestern Pennsylvania, where, between 1858 and 1859, a new successful pattern developed to produce oil in commercial quantity. From 1861, that innovative process put the United States in the position to gain increasing shares in the young European mineral oil markets and, subsequently, to jeopardize the position of local oil (vegetal, animal and mineral) producers. The second part, using a national case study approach, explores the history of a British oil company operating in Romania since 1863, the Wallachian Oil Company. This venture by London stockholders-short, difficult, and abortive-is a mirror of the nature of the business implemented by emerging oil companies, not only from Europe, and therefore exemplifies the challenges of setting the modern oil sector in motion in the nineteenth century.