 According to medieval historian Lynn Thorndike, people in Medieval Europe probably bathed more than people did in the 19th century.Some time after Louis Pasteur's experiments proved the germ theory of disease and Joseph Lister and others put them into practice in sanitation, hygienic practices came to be regarded as synonymous with health, as they are in modern times.Many religions require or encourage ritual purification via bathing or immersing the hands in water.