condictio causa data causa non secuta in Roman law, the personal action for non-materialization of one side of a bilateral agreement. Originally its scope was narrower, applying to cases where one side of innominate real contract had been performed and the other person pulled out. This action allowed for a claim to be made for a return. The terminology is much used in Scots law. It is known in many modern civilian systems. It is a remedy for unjust enrichment and provides restitution.