The ancient Romans developed the most advanced public health systems of the ancient world, with aqueducts to provide clean water and sewers to remove waste.

These systems fell into disuse in medieval Europe, where urban sanitation was extremely poor, contributing to the spread of disease.

Early public health measures included the use of quarantine, isolating ships and people during epidemics like the Black Death.

The 19th century saw the rise of the sanitary reform movement in response to the terrible health conditions in industrial cities.

Reformers like Edwin Chadwick in Britain used statistics to prove the link between poor sanitation and disease.

Major public works projects, such as the construction of modern sewer systems in London and Paris, were undertaken in the mid-19th century.

The scientific discoveries of Louis Pasteur (germ theory) and Robert Koch in the late 19th century provided a scientific basis for public health.

These discoveries led to the development of pasteurization, antiseptics, and the identification of the bacteria that cause specific diseases.

The 20th century saw massive improvements in public health due to clean water, vaccination programs, and the discovery of antibiotics.

Public health measures have been one of the most important factors in the dramatic increase in human life expectancy.