Explanations of the expansion -  

In hist book "Svitjod  resor till Sveriges ursprung" (1998) about the Svear,  Mats G. Larsson argues that one possible reason for the increase in overseas voyages is that political cohesion at home meant that young men seeking fame and fortune began travelling more abroad rather than raid neighbours in Scandinavia (although these, of course, continued). Should we mention this as on of the possible explanations? Cheers