. . . . "Foster" . "Fosterage, the practice of a family bringing up a child not their own, differs from adoption in that the child's parents, not the foster-parents, remain the acknowledged parents. In many modern western societies foster care can be organized by the state to care for children with troubled family backgrounds, usually on a temporary basis. In many pre-modern societies fosterage was a form of patronage, whereby influential families cemented political relationships by bringing up each other's children, similar to arranged marriages, also based on dynastic or alliance calculations." .