Medical views on the value and risks of tobacco use have changed radically over the centuries. In the 16th century, tobacco was introduced to continental Europe as a medicinal plant and quickly rose to become a "cure-all." When hedonistic pipe smoking became widespread in continental Europe during the Thirty Years' War, physicians warned of the consequences of tobacco abuse. For centuries, tobacco herb was now considered both harmful and curative.The sharp increase in tobacco consumption in the first decades of the twentieth century correlated with an increase in lung cancer, which until then had been little observed. Statistical proof of the direct correlation was provided in the twenties and thirties by Fritz Lickint, among others. In 1939, the Cologne physician Franz Hermann Müller presented the first case-control study on the relationship between smoking and lung carcinoma, which received little international attention. The epidemiological studies published in the 1950s by English and American scientists were based on the same scientific approach as Müller's work but were now considered groundbreaking.