exceptio spolii

Etymology
Literally, “exception of spoil”. Derived from the False Decretals of (9th century); originally applied to bishops who had been deprived of property by the secular government, but subsequently generalised.

Noun

 * 1)  The legal doctrine that anyone who has been deprived of their property must have their property restored to them before their dispossessor can validly bring a charge against them.