Two polio vaccines are used throughout the world to combat polio. The first was invented by Jonas Salk, and first tested in 1952 and announced to the world by Salk on March 26, 1953. It consists of an injected dose of killed polio virus. Albert Sabin[?] produced a cheaper and more effective oral polio vaccine in 1962.
... basis of authority.
The first to have the title of "Tyrant" was Pisistratus in 560 BC.
In modern times Tyrant has come to mean a dictator who rules with ...