Augustus Caesar, the first Roman Emperor in 27 BC with confirmation of powers by the Senate in 23 BC and 19 BC, sent a clear, strong message of change in Roman political philosophy.  With institution of the emperor into the figure-head descriptors of the heads of state, the social and political problems of the old system were gradually replaced with royal family intrigue and Praetorian (military corruption). 

To clear the path for expansion, Octavian had Caesar’s only son executed; thereby, reducing the complication of family ties.  Augustus avoided a myriad of social problems through very clever political maneuvering and manipulation, (in particular, avoiding the direct or indirect use of the title King, winning overwhelming support of the masses and maintaining absolute control of the Roman Elite Legions.

The Roman Legions had grown to approximately 50 due to the number of civil wars.  These were reduced to 28 with the less loyal disbanded.  Augusta also created nine special cohorts supposedly to maintain peace in Italy.   Three of these were stationed in Rome and became known as the Praetorian Guard.

Through Settlements Numbers 1 and 2 approved by the Senate, Augustus was enabled to (1) have the taxes of Italy flow to his Egypt fiefdom, (2) to be given the right to interfere in any province and override the decisions of any governor and 3) all armed forces within the city were under the sole authority of Augustus.

In an attempting to secure the borders of the Empire upon the Rivers Danube and Elbe, Augusta ordered the invasion of Illyria, Moesia and Panmonia, south of the Danube, and Germania, west of the Elbe.  The Illyrian province revolted and three full Legions under the command of General Varus were ambushed and annihilated at the battle of Teutoburg Forest in 9 AD by Germanic tribes led by Arminius.  This was the bloodiest defeat suffered by the Elite Roman Legions in their entire existence.  The stalemate became the borders. Because of Augustus, the destructive decline was halted and slowed for another five centuries.  Under the aegis of Augustus, the population of Rome reached 1,000,000 apparently satisfied citizens.

Augustus quietly acquired almost absolute political power retaining only an outward pretense of the former Republican form of government.   His designated successor, Tiberius (14 -37 AD), took power without any serious opposition and establish the Julio-Claudian dynasty (14-68 AD) which lasted until the death of Nero (68 AD).  The territorial expansion of the Roman Empire continued and the Empire remained secure despite a series of emperors that were widely view as corrupt, if not depraved; e.g., Caligula (377-41 AD).  Claudius (41-54) improved the bureaucracy and streamlined the citizenship and senatorial rolls.  He led the conquest and colonialization of Britian (43 AD). He created the winter port for Rome at Ostia.

Followed by Nero, who negotiated peace with the Parthian Empire (58-63 AD).  He is remembered as the tyrant that “fiddled while Rome burned” in 64 AD. 
The main enemy in the west was the barbarian tribes beyond the Danube and the Rhine rivers.  They were violent and feared, but mostly fought amongst themselves.  In the east, the enemy was Parthia (Persia). 
The period of 68-69 AD became known as the “Year of the Emperors.”  There were four suicides Nero, Galba, Otho and Vitellius until Emperor Vespanian of the Flavian Dynasty.  Civil wars had been rampant, Vespanian gave stability; however, his administration tended toward centralization and a move to Imperator (dictator).  Vespanian brought fiscal control and commissioned the Colosseum.  He reassigned the newly recruited Roman Legions away from the areas of their initial recruitment to Gaul and Spain.  Emperor Titus followed (79-81 AD).  Disasters shortened his reign:  Eruption of the Volcano, Vesuvius (79) and the devastating fire of the City of Rome 80 AD.