A Viking raid nearly always came as a total surprise. The Vikings were expert navigators and knew the coasts of Europe like the back of their hand. They decided on a target and planned the attack in advance. Having the fastest ships of the day they would arrive seemingly out of nowhere close to the target and storm ashore ready to attack.
If needed, they could row their ships up rivers and if the target was some distance from the river they would leave their ships, round up available local horses and head for the church, convent or village of their choice. They often had superior weapons and were well trained, and usually got what they wanted. After the raid they would return to their ships and sail away. For the people attacked it was difficult to organise a defence, because of the speed with which everything happened. The effect on the people then would be be similar today to an attack by troops brought in by helicopters to attack a peaceful small town.
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