Vladimir Monomakh in his Kiev reigning (1113-1125) was able to keep unity of the Ancient Russian state and to extinguish separative aspirations of some princes (Yaroslav Svyatopolchich, Glev Vseslavich Minsky).
In the field of foreign policy he managed to repel danger from the Polovtsy; one of the hordes, led by the son of Sharukan - Otrok, was even compelled to leave Don region and went to Northern Caucasus. In 1116 or 1118 Vladimir organized full-scale military and political offensive to Byzantium.
The purpose of the Kiev prince was to put on Konstantinopol throne his son-in-law Leon pretending to be a son of Byzantian emperor Roman IV Diogen, and after his death (as a result of murder inspired by emperor Alexey I Komnin) - his grandson Vasily. These attempts failed, but their result was the consolidation of Russian influence on the left bank of the Lower Danube.
In 1125 - 1132 senior son of Monomakh Mstislav Vladimirovich was the Kiev prince. It was last period of relatively political unity of Russia. After Mstislav's death, in government of his brother Yaropolk (1132-1138), disintegration of the state into actually independent princedoms got irreversible character.
Wide international communications of Russia in XI - first half of XII are well illustrated by the data about matrimonial communications of Russian princely dynasty.
So, Yaroslav the Wise married to daughter of the Swedish King - Ingigerd, his daughters were married to: Anastasia - Hungarian King Andrey, Elizabeth - Norwegian King Harald, and after his death - Danish Svein, Anna - King of France Heinrich I.
Vsevolod Yaroslavich married to the daughter of Byzantian emperor Konstantin Monomakh, his son Vladimir - to Gita, daughter of last Anglo-Saxon king Garald, killed in the battle of Hastings in 1066. The wife of Mstislav Vladimirovich was a daughter of Swedish king Christina. Marriages of Russian princes and daughters of the nearest neighbours - Polovetsky khans were usual.