The period of transition

The era that began when Julius Caesar crossed the Rubicon in 49 BC and ended when Octavian returned to Rome after Actium in 29 BC, saw the constitutional evolution of the prior century accelerate at a rapid pace. By 29 BC, Rome had completed its transition from being a city-state with a network of dependencies, to being the capital of a world empire.[68] With Pompey defeated and order restored, Caesar wanted to ensure that his control over the government was undisputed. The powers which he would give himself would ultimately be used by his imperial successors.[69] He would assume these powers by increasing his own authority, and by decreasing the authority of Rome's other political institutions. Caesar would hold both the dictatorship and the tribunate, but alternated between the consulship and the proconsulship.[69] In 48 BC, Caesar was given permanent tribunician powers. This made his person sacrosanct, gave him the power to veto the senate, and allowed him to dominate the Plebeian Council. In 46 BC, Caesar was given censorial powers,[70] which he used to fill the senate with his own partisans. Caesar then raised the membership of the Senate to 900.[71] This robbed the senatorial aristocracy of its prestige, and made it increasingly subservient to him. While the assemblies continued to meet, he submitted all candidates to the assemblies for election, and all bills to the assemblies for enactment. Thus, the assemblies became powerless and were unable to oppose him.[72] Near the end of his life, Caesar began to prepare for a war against the Parthian Empire. Since his absence from Rome would limit his ability to install his own consuls, he passed a law which allowed him to appoint all magistrates in 43 BC, and all consuls and tribunes in 42 BC. This, in effect, transformed the magistrates from being representatives of the people to being representatives of the dicta or. The Parthian Empire (Persian: ?), (/?p?r?i?n/; 247 BC – 224 AD), also known as the Arsacid Empire (/rs?s?d/; Modern Persian: Ashkanian), was a major Iranian political and cultural power in ancient Persia. Its latter name comes from Arsaces I of Parthia who, as leader of the Parni tribe, founded it in the mid-3rd century BC when he conquered the Parthia region in Iran's northeast, then a satrapy (province) in rebellion against the Seleucid Empire. Mithridates I of Parthia (r. c. 171–138 BC) greatly expanded the empire by seizing Media and Mesopotamia from the Seleucids. At its height, the Parthian Empire stretched from the northern reaches of the Euphrates, in what is now south-eastern Turkey, to eastern Iran. The empire, located on the Silk Road trade route between the Roman Empire in the Mediterranean Basin and Han Empire of China, became a center of trade and commerce. The Parthians largely adopted the art, architecture, religious beliefs, and royal insignia of their culturally heterogeneous empire, which encompassed Persian, Hellenistic, and regional cultures. For about the first half of its existence, the Arsacid court adopted elements of Greek culture, though it eventually saw a gradual revival of Iranian traditions. The Arsacid rulers were titled the "King of Kings", as a claim to be the heirs to the Achaemenid Empire; indeed, they accepted many local kings as vassals where the Achaemenids would have had centrally appointed, albeit largely autonomous, satraps. The court did appoint a small number of satraps, largely outside Iran, but these satrapies were smaller and less powerful than the Achaemenid potentates. With the expansion of Arsacid power, the seat of central government shifted from Nisa, Turkmenistan to Ctesiphon along the Tigris (south of modern Baghdad, Iraq), although several other sites also served as capitals.