In order to realize the assignment of rights , the Romans took the following methods in turn : novatio , litigation proxy , the notice of litigation , and the inheritance of creditor s ’ rights . And in Justinian times , the Romans had gradually recognized general assignment contract .

罗马人相继采用了债的变更、诉讼代理、诉讼通知和债权继承等方式来达到债权让与的目的，至优士丁尼时代，人们逐渐认可一般的让与契约。