Apostles

Why do some Christian leaders today give themselves the title of Apostle? Is there some sort of Christian accreditation board handing these titles out?! Or do they honestly feel so entitled as to call themselves an Apostle? As I understand it the Bible defines an Apostle as someone who had seen Jesus' ministry and resurrection and could attest to these events as an eyewitness. This would seem to suggest that the office of apostle is no longer an active role, or is it? I believe that the role of the Apostles is still being carried out today, but not by those whom you might think. Instead, the writings of the Apostles (contained in scripture) continue to carry out their responsibility and calling. They might be dead but their words live on still providing testimony of the risen Christ. So please, call youselves a Pastor, an Elder, a Bishop if you must... but please take the title "Apostle" off your letterhead.