The Pope
Octavian
Augustus was not the ruler of a country. He was the ruler of an empire: the Roman Empire.
No ruler actually MADE Christianity a world religion; rather it was the efforts of individual travellers who spread the Gospel throughout the known world. However, the first Christian Roman Emperor was Constantine, and as the Roman Empire was the dominant superpower of the time, he would be the nearest to your question.
Augustus was the ruler of the Roman Empire when the Aeneid was written. In fact, he specially commissioned Virgil to write it.
Charlemagne was the first ruler of the Holy Roman Empire.
The emperor
Octavian defeated Antony and became the first ruler of the Roman Empire.
A collection of kingdoms under one powerful ruler is known as an empire. Examples of empires can be seen throughout history, the Roman Empire, the Ottoman empire, the Mongol Empire, and the British Empire, just to name a few.
Diocletian was the Roman Empire in the late 200's
Augustus caesar
Calilgula
Julius was a very famous roman ruler, who ruled the roman empire.