This article deals with the Ancient Russian Empire from the early 13th Century when Kiev was split into small kingdoms and ruled by Russian princes. Due to the lack of unity and the selfishness of these princes, these kingdoms were lost to the Mongols who sent troops to attack them and took control of the Russian Empire for 243 years. This article begins with a presentation of the time when the Russian Empire was under the Mongol yoke ends with the time when it became independent. It presents the lives and work of eleven Russian princes who ruled Moscow, starting with the reign of Prince Alexandravich, who first ruled in 1263, until the end of the reign of Prince Ivan IV in 1584. The article also describes the establishment of the City of Moscow, which was encouraged by the expansion of the Empire under the rule of Prince Vladimir at the time when the City of Vladimir was the centre of the Ancient Russian Empire. The Prince of Moscow had to fight against many princes of major cities in order to obtain an appointment certificate from the Mongol Khan in order to represent the Khan in administration and to collect levies for him. Later, in the middle of the 14th century, the Prince of Moscow was selected to be leader of the Ruses and Moscow became the centre of the Empire. The City of Vladimir, which was close by, came under the rule of the Prince of Moscow. Other cities and towns were also annexed to Moscow, enabling the Ruse Empire to become unified and eventually gain independence.