The relations of Slavs (the Rus) with Azerbaijan possessed traditional character from the early Middle Ages-Slovanic tribes traded in Azerbaijan by the vehicle of sea and river ways and through the territory of Azerbaijan they dealed in other countries of Caliphate. But, beginning from the end of 9th and at the beginning of 10th centuries, at the result of the establishment of Kiev Rus state the coming of the Rus here began to be related with not trade but plunders and capture.
In 909, they entered to the Caspian Sea with their lots of ships, captured the Iceland of Abaskun in the south of the sea and plundered seaside regions. But the resisted local population defeated the Rus. In 910, the Rus again invaded to Azerbaijan, plundered and burned the isle of Sari and the seaside settlements too. Obtaining lots of trophies and profits, they directed to the Iranian shore of Caspian Sea, but there they encountered with the army of GilanShah, were defeated and obliged to recede; the receded forces of the Rus were withdrawn by the troops of ShirvanShah.
In 913, the Rus organized new, much bigger campaign. They promised the half of profit and trophy to Khazar Khagan, if the last permited them to cross from his territory. The armed forces of the Rus moved in the Caspian Sea with 500 ships and approached to Baku. The population of the city and the nearest villages did not wait such attack from the sea and that’s why were sprained to the plunder and destruction. The Rus settled their camp in the nearest island, where they implemented attacks to seaside regions and to the isle of Sari. As they promised, the Rus sent the half of the trophy to the Khazar khagan, but the muslim population and Turkish soldiers, who heard about the destruction of their co-religionist, appealed to the khaqan with the request to punish foreigners. In the cruel battle between turks and slavs, which lasted three days, the Rus were destroyed and only little part of them could survive. After this battle, the Rus did not dare to organize raids to the territory of Azerbaijan for 30 years.
The raids of the Rus to Azerbaijan lands continued later. Istead of the unite against the enemy, several governors called their armed forces for the aid in local wars. In 1030, there happened such event: The Rus, who attacked to the Caspian shore with 38 ships and armed forces destroyed the army of ShirvanShah near the fortress of Baku and directed to the up, through the river of Aras. The governor of Shaddadids, the son of Fazl ibn Muhammed, Musa paid them lots of money and called them to help him in the suppression of Beylagan uprising, led by his brother Askariyya. Musa, who overwhelmed his brother Askariyya and pressed the revolt in Beylagan rewarded the Rus with valuable presents and they returned to their country through the territory of Byzantine.
In 1032-1033s, Shirvan was sprained to the next destructive attack.
Alanians and sarirs, together with their ally, Rus captured the capital of ShirvanShahs, Yezidiyya, destroyed the city and plundered the civil people for 10 days. In this invasion, about 10 thousand settlers of Shirvan were killed. Nevertheless, the nation, which rose against the invaders withdrew foreigners from their land. The governor of Derbend, emir Mansur ibn Maymun also inflicted to damage them. The Rus and alanians attacked to Derbend in the next year, i.e. in 1033 for revenge, but they were defeated again. So, since the end of the 9th century Azerbaijan was sprained to several attacks of the Rus. Plenty of local foughts, which weakened the country, as well as the absence of military fleet were the major reasons, which aggravated the resistance of local population against foreign invaders. Taking into account that the Rus invaded to Azerbaijan from the sea, then the absence of the navy was the major/essential cause, which aggravated the defence of people and lands from marine pirates of the North.
So, in the 9th-11th centuries, Azerbaijan nation and Azerbaijan feudal states were able to preserve their independence and freedom, despite of great difficulties and losts.