Was John Wayne arguably the greatest western star ever?
In terms of quantity, quality, and longevity you can mqake a strong argument in favor of John Wayne
I shall assume you mean King John of England who lived from 1167 to 1216. John was quite the controversial monarch, arguably one of Britian's most. However, if it were not for his blunders we would not have the foundation of the western laws we have today. In 1215 before his death John signed a document known as the Magna Carta; also arguably one of the most important documents to Western law as it guarenteed…
Wayne played the Roman centurion who said, "Truly this was the son of god." It was a "famous" line only in the sense that Wayne's appearance sticks out like a sore thumb -- you can't help but ask, "Why is John Wayne pretending to be a centurion?" There is also an apocryphal story about George Stevens trying to get Wayne to say the line in the proper manner.