Wikipedia
Condition subsequent
A condition subsequent is an event or state of affairs that brings an end to something else. A condition subsequent is often used in a legal context as a marker bringing an end to one's legal rights or duties. A condition subsequent may be either an event or a state of affairs that must either (1) occur or (2) fail to continue to occur.
Usage examples of "condition subsequent".
On the other hand, every condition subsequent is precedent to the incidence of the burden of the law.