What makes John Unitas the greatest quarterback of all-time is that he was able to do things in an era where the rules benefited the defense that are considered amazing today. In an era where the rules benefit the offense like driving his team down the field in a couple of minutes to win the game. Perhaps with just one or two timeouts if any. Pass after pass, completion after completion. And the other thing being that Unitas called his own plays. And had to make all the decisions as well. So he had both great physical skills with his arm and mobility, as well as vision. But also great mental and leadership skills in knowing what plays to call and when to call them.