Wang, after the defeat of Zhai and Liu Xin becoming even more convinced that the empire is entirely under his control, decides to finally seize the throne and start a new dynasty.

After receiving a false prophecy written by the hoodlum Ai Zhang that purports to be a divine decree from Emperor Gaozu (Liu Bang) stating that the throne should be given to Wang, and that Grand Empress Dowager Wang should follow this divine will,  Wang in the winter of 8-9 issues a decree accepting the position of emperor, establishing the Xin Dynasty.

The self-confident Wang Mang believes that he now has the power to implement his ideals of restoring the legendary golden age of the early Zhou Dynasty.

To this end, he modifies the governmental structure in many ways to conform with Zhou standards.

He also continues the regime of modifying geographical names to fit with ancient names (or more euphemistic names, as he sees fit)—so much so that even imperial edicts discussing the locations by their new names are forced to include notes on the old names so that the recipients of the edicts can tell what locations he is referring to.

As part of this regime, the capital Chang'an's name is changed as well, involving the change of a homophonous character: literally, long peace, to, literally, enduring peace.

Wang Mang creates his wife, Lady Wang, empress.

By this point, only two of her four sons are still alive.

The older, Wang An, is described as lacking in talent; Wang makes him the Lord of Xinjia.

Wang makes the younger, Wang Lin, crown prince, and appoints several Confucian scholars to advisors him.

Grateful to his aunt Grand Empress Dowager Wang (who, however, resents him for deceiving her and usurping the throne), continues to honor her as empress dowager, but also gives her an additional title of Wangmu, the same title carried by the mother of King Wen of Zhou, implying that she is also his mother and had helped establish a new dynasty.

In 9 also, Wang Mang institutes a revolutionary land redistribution system, ordering that all land in the empire become legally the property of the empire, to be known as wangtian, in a system similar to the Zhou well-field system.

All further land transactions are banned, although property owners are allowed to continue to possess the property.

However, if a family has less than eight members but has one "well" or larger property (about 0.6 km²), it is required to distribute the excess to fellow clan members, neighbors, or other members of the same village.

Criticism of the wangtian system is punishable by exile.

Wang also abolishes slavery.

In 9, after Wang Mang has usurped the throne, Liu Kuai, the Marquess of Xuxiang, attacks the Dukedom of Fuchong, held by his brother Liu Ying, the former Prince of Jiaodong.

He is defeated and dies while fleeing from the battle.

Wuhuan had become somewhat of a dual vassal to both the Han and the Xiongnu during the late Han Dynasty, and, under a policy in effect since 121 BCE, is supposed to pay Xiongnu tributes in textile and leather.

Should Wuhuan fail to pay the tributes, Xiongnu forces kidnap Wuhuan women as hostages.

The first sign of irritation with Wang Mang’s policies had come sometime before 10, by which time the Xin director of Wuhuan affairs had informed the Wuhuan tribes not to pay further tribute to Xiongnu.

In response, the Xiongnu mount a punitive military action against Wuhuan, taking hostage about one thousand women and children.

At Wang Mang's orders, the Xiongnu are later forced to return the Wuhuan hostages.

Rivalry between Maroboduus and Arminius, the Cheruscan leader who inflicts the devastating defeat at the Battle of the Teutoburg Forest on the Romans under Publius Quinctilius Varus in 9 CE, prevents a concerted attack on Roman territory across the Rhine in the north (by Arminius) and in the Danube basin in the south (by Maroboduus).

However, according to the first century CE historian Marcus Velleius Paterculus, Arminius sent Varus' head to Maroboduus, but the king of the Marcomanni sent it to Augustus.

Tiberius and Germanicus launch an operation against the Daesitiatesin the next year.

Bato and the Daesitiates after fierce battles surrender to Tiberius in  September CE 9, only a few days before the Battle of Teutoburg Forest.

This is just in time: the Roman high command does not doubt that Arminius and the Cherusci would have formed a grand alliance with the Illyrians.

It has taken the Romans three years of hard fighting to quell the revolt, which is described by the Roman historian Suetonius as the most difficult conflict faced by Rome since the Punic Wars two centuries earlier.

It is alleged that when Tiberius asked Bato and the Daesitiates why they had rebelled, Baton was reputed to have answered: "You Romans are to blame for this; for you send as guardians of your flocks, not dogs or shepherds, but wolves."

Bato will spend the rest of his life in the Italian town of Ravenna.

Augustus, as part of his ongoing effort to increase the Roman populace, passes the Lex Papia Poppaea in CE 9, promoting large families.

It includes provisions against adultery and celibacy and complements and supplements Augustus' Lex Julia de Maritandis Ordinibus of 18 BCE and the Lex Iulia de Adulteriis Coercendis of 17 BCE.

The law is introduced by the suffect consuls of this year, M. Papius Mutilus and Q. Poppaeus Secundus, although they themselves are unmarried.

The rebellion in the Balkans has only just been completed when Arminius raises the Germans against their Roman governor Varus and destroys him and his three legions.

As Augustus cannot readily replace the troops, the annexation of western Germany and Bohemia is postponed indefinitely; Tiberius and Germanicus are sent to consolidate the Rhine frontier.

Wang, seeking to control fluctuations in the prices of food and textiles by purchasing excess goods and then selling them when prices rise, establishes a state economic adjustment agency in 10.

The same agency also becomes responsible for loaning money to entrepreneurs, at the rate of three percent per month.

Six offices are set up: in Luoyang, …

…Handan, …

…Linzi (modern Zibo, Shandong), …

…Wancheng (modern Nanyang, Henan), …

…Chengdu, and …