Page "Medieval warfare" Paragraph 105

Almost by definition opponents of the Vikings were ill prepared to fight a force that struck at will, with no warning.

European countries with a weak system of government would be unable to organize a suitable response would naturally suffer the most to Viking raiders.

Viking raiders always had the option to fallback in the face of a superior force or stubborn defence and then reappear to attack other locations or retreat to their bases in what is now Sweden, Denmark, Norway and their Atlantic colonies.

As time went on, Viking raids became more sophisticated, with coordinated strikes involving multiple forces and large armies, as the " Great Heathen Army " that ravaged Anglo-Saxon England in the 9th century.

In time the Vikings began to hold on to the areas they raided, first wintering and then consolidating footholds for further expansion later.