Pope Leo I

Leo I (; c. 400 – 10 November 461), also known as Leo the Great, was an Italian priest of the Roman Catholic Church and the 45th Pope from 29 September 440 to his death on 10 November 461.
Early life.
Nothing is known about his early life. Little is known about his early work in the church. The first unmistakable reference to Pope Leo is in 429 when he was only a deacon.
Pope.
Leo was made Bishop of Rome on 29 September 440. In other words, he became pope.
Leo is one of only two popes who are called "the Great". The other "great" is the first pope named Gregory.
In 452, Leo I peacefully convinced Attila the Hun "not" to destroy and plunder Rome. This made him a legendary figure in Italy.
Leo also wrote many scholarly books. One of them, a "Tome" on the Nature of Christ, was read out to both the Roman Emperor and to the Patriarch of Constantinople. Afterwards, they followed Leo's recommendations, and officially accepted certain religious matters, and rejected others. These decisions had many political implications, in many areas of the Eastern Roman Empire, for centuries to come.