The name cholera had been used in previous centuries to describe illnesses involving nausea and vomiting. Today, cholera specifically describes illness caused by the Vibrio cholerae bacteria. There are numerous examples of epidemics prior to 1817 which are suspected as being cholera. In the sixth century BCE cholera-like symptoms were described by an Indian text. Indeed, descriptions of a disease in India from as far back as 2,500 years ago describe an illness reminiscent of cholera. Greek physician Hippocrates wrote about an illness resembling cholera about 2,400 years ago, as did Roman physician Galen roughly 500 years later in the 2nd century. In the 16th century, an outbreak of acute diarrhea was reported to have occurred in the East Indies by the Dutch. A similar outbreak was recorded in 1669 in China. However, there is not evidence of "true Asiatic Cholera" prior to 1781, in which the first well-documented epidemic occurred. Having begun in southern India, it would later spread to eastern India and eventually Sri Lanka. Cholera was endemic to the lower Ganges River. At festival times, pilgrims frequently contracted the disease there and carried it back to other parts of India on their returns, where it would spread, then subside.  The first cholera pandemic started similarly, as an outbreak that was suspected to have begun in 1817 in the town of Jessore. Some epidemiologists and medical historians have suggested that it spread globally through a Hindu pilgrimage, the Kumbh Mela, on the upper Ganges River. Earlier outbreaks of cholera had occurred near Purnia in Bihar, but scholars think these were independent events. In 1817, cholera began spreading outside the Ganges Delta. By September 1817, the disease had reached Calcutta on the Bay of Bengal and quickly spread to the rest of the subcontinent.  By 1818 the disease broke out in Bombay, on the west coast.