Hospitals existed in Asia Minor, Sri Lanka and Hindustan as far back as 1000 BC. Typically, shrines to deities doubled as centers of healing in early Asian and Persian societies. The conquests of the Roman Empire and the spread of Christianity around 300 AD led to the establishment of "valetudinaria" military hospitals across Europe and Northern Africa. Public hospitals in the secular, modern sense began to emerge in Europe and North America in the 18th century after the Enlightenment period.
There is debate among scholars as to what constitutes the first historical example of a hospital. Religion was the dominant influence in the creation of hospitals until well after the Crusades were over, and the first recognizable hospitals were almost certainly founded and run by Christian orders such as the Brother Hospitallers of Saint John in Spain and France and the Benedictine monks of Europe.
The first modern hospitals in the Middle East were also established by religious figures in the name of aiding the sick and the poor. Massive Islamic hospitals were founded in Baghdad and Damascus by Arabs, and in Valencia, Spain by transplanted Moors. The construction and maintenance of general public hospitals by secular establishments and state governments did not occur until at least the 16th century; all hospitals before that time were built for religious or military purposes.