At some point early in the Viking Age, a group of Northmen came across a natural harbor on the western side of the Irish Sea. Being that they were a seafaring people, having places in foreign lands where they could safely make port was a significant advantage. Orkney was already showing its usefulness, and now they needed another waypoint further south. The life of a northman, even the life of a Vikingr, involved a lot more travelling and trading than it did actual raiding. So having friendly trading spots along their route wasn’t just convenient, it was good business.