Specification of the earliest institution devoted primarily to the treatment of the mentally ill in the western world remains elusive. Uncertainty arises from limited documentation and gradual evolution of most candidate sites from hospices for the poor, foreign, or homeless, or as clinical centers for the care of a range of persons with general medical and psychiatric disorders. Plausible candidates identified in the late fourteenth and early fifteenth centuries include Bethlem Asylum in London. Much less often considered are two centers in medieval Spain: the Moorish Maristan at Granada (1365) and the Christian Hospital of Our Lady Mary for Lunatics, the Insane and Innocents at Valencia (1409). Since the early Spanish sites are not well known, we have summarized available information concerning their foundation, facilities, theories and practices, as arising from the cultural and political background of the times and regions.