The Romans were ahead of their time and had knowledge that no other civilization had at the time, countries would benefit from the knowledge the Romans possessed and would receive 'for example' better trade and knowledge of other civilizations.
The Roman Empire became ancient history.
The Byzantine Empire.
Find out what the reasons were and decided what were not the reasons.
It never did. The so-called Holy Roman Empire was a mid-European entity.
There were many reasons for the success of the Roman empire. The major reasons were their superior army, their granting of citizenship, their ability to absorb aspects of other cultures and their organization.
The Holy Roman Empire had nothing to do with the Romans. It was a medieval institution centred around Germany. The Roman republic became an empire by expansion both before and after the Punic wars.
Augustus Caesar became emperor of the Roman Empire in 27 B.C.
Egypt became part of the Roman Empire in 30 bc
After the Emperor Constantine converted to Christianity, that became the official religion of the Roman Empire.
Christianity was forced upon the people of the Roman empire by the emperor Theodosius I in 380 AD.
Syria became a province of the Roman empire in 64 BC, after the Third Mithridatic War.
Invasion by Germanic tribes and by Huns.