Medicine progressed during Queen Victoria's reign. In fact, medicine at the start of the nineteenth century was little different from that in the medieval era whereas by the end of the century, it became a lot closer to twenty-first century practice thanks to advances in science, especially microbiology, paving the way for the germ theory of disease. This was during the height of the Industrial Revolution, and urbanisation occurred at a frantic pace. As the population density of the cities grew, epidemics of cholera, smallpox, tuberculosis, and typhus were commonplace.