That means that the play was without fail written after (in Latin, post) 1587.
This usually requires what is commonly known as a "dating method".
Carbon-14 dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 50,000 years old.
It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities.
In this relative dating method, Latin terms ante quem and post quem are usually used to indicate both the oldest and the most recent possible moments when an event occurred or an artifact was left in a stratum.
But this method is also useful in many other disciplines.
What methods do they use and how do these methods work?