Vespasian was a remarkably successful Roman general who had been given rule over much of the eastern part of the Roman Empire. He had supported the imperial claims of Galba, after whose death Vespasian became a major contender for the throne. Following the suicide of Otho, Vespasian was able to take control of Rome's winter grain supply in Egypt, placing him in a good position to defeat his remaining rival, Vitellius. On December 20 69, some of Vespasian's partisans were able to occupy Rome. Vitellius was murdered by his own troops and, the next day, Vespasian, then sixty years old, was confirmed as Emperor by the Senate.

Although Vespasian was considered an autocrat by the senate, he mostly continued the weakening of that body that had been going since the reign of Tiberius. The degree of the Senate's subservience can be seen from the post-dating of his accession to power, by the Senate, to 1 July, when his troops proclaimed him emperor, instead of 21 December, when the Senate confirmed his appointment. Another example was his assumption of the censorship in 73, giving him power over the make up the Senate. He used that power to expel dissident senators. At the same time, he increased the number of senators from 200, at that low level because of the actions of Nero and the year of crisis that followed, to 1,000; most of the new senators coming not from Rome but from Italy and the urban centers within the western provinces.

Vespasian had to pay the finacial burdens of Nero's excesses and the civil wars. To do this, he not only increased taxes, but created new forms of taxation. Also, through his power as censor, he was able to carefully examine the fiscal status of every city and province, many paying taxes based upon information and structures more than a century old. Through this sound fiscal policy, he was able to build up a surplus in the treasury and embark on public works projects. It was he who first commissioned the Amphitheatrum Flavium (Colosseum); he also built a forum whose centerpiece was a temple to Peace. In addition, he allotted sizable subsidies to the arts, creating a chair of rhetoric at Rome.

Vespasian was also an effective emperor for the provinces in his decades of office, having posts all across the empire, both east and west. In the west he gave considerable favoritism to Hispania (the Iberian Peninsula, comprising modern Spain and Portugal) in which he granted Latin rights to over three hundred towns and cities, promoting a new era of urbanization throughout the western (formerly barbarian) provinces. Through the additions he made to the Senate he allowed greater influence of the provinces in the Senate, helping to promote unity in the empire. He also extended the borders of the empire, mostly done to help strengthen the frontier defenses, one of Vespasian's main goals. The crisis of 69 had wrought havoc on the army. One of the most marked problems had been the support lent by provincial legions to men who supposedly represented the best will of their province. This was mostly caused by the placement of native auxiliary units in the areas they were recruited in, a practice Vespasian stopped. He mixed auxiliary units with men from other areas of the empire or moved the units away from where they were recruited to help stop this. Also, to reduce further the chances of another military coup, he broke up the legions and, instead of placing them in singular concentrations, broke them up along the border. Perhaps the most important military reform he undertook was the extension of legion recruitment from exclusively Italy to Gaul and Hispania, in line with the Romanisation of those areas.