Mission Indians were from many regional Native American tribes; their members were often relocated together in new mixed groups and the Spanish named the Indian groups after the responsible mission. For instance, the Payomkowishum were renamed "Luiseños" after the Mission San Luis Rey and the Acjachemem were renamed the "Juaneños" after the Mission San Juan Capistrano. The Catholic priests forbade the Indians from practicing their native culture, resulting in the disruption of many tribes' linguistic, spiritual and cultural practices. With no acquired immunity to the new European diseases and changed cultural and lifestyle demands, the population of Native American Mission Indians suffered high mortality and dramatic decreases especially in the coastal regions where population was reduced by 90 percent between 1769 and 1848.