In the Middle Ages , most of the present territory of Moldova was part of the Principality of Moldavia , and in 1812 it became part of the Russian Empire , under the name of Bessarabia .
In the Middle Ages , 90 % of the present territory of Moldova was part of the Principality of Moldavia . 
 In 1812 , the Russian Empire annexed the estern half of Moldavia , which became known under the name of Bessarabia .