They mainly survived by farming, fishing and piracy. The reasons why the Vikings began to expand are unclear, since they left no record of their intentions. There is, however, broad agreement among historians, from the artifacts left by the raided peoples, that looting was the primary motive behind their raids. From the beginning of the sixth to the end of the eight century, the European mainland was more or less free of external invasion. The earliest documented raids by the Vikings began in 793 at Lindisfarne, England.
Historians distinguish three phases to the raids.
The first phase of attacks was from 790-840. The Vikings used shallow draught longships which were ideally suited for surprise raids on coastal locations that struck terror into their victims. The attacks were usually seasonal and isolated in small bands. These attacks began along the coastal cities in England and France and continued down along the river communities. The Carolingian Empire was deeply affected by the raids at this time.