According to wikipedia an Antipope is: "An antipope (Latin: antipapa) is a person who, in opposition to the one who is generally seen as the legitimately elected Pope, makes a significantly accepted competing claim to be the Pope, the Bishop of Rome and leader of the Catholic Church."
The person that is Antipope between Benedict VI and Benedict VII and between John XIV and John XV is the same person. The Antipopes with the same name opposed to Martin V are not the same persons. This is also the case for the Antipopes that oppose Innocent II and Alexander III.
In this quiz you can use both the common English name and the Latin name of the Antipopes.