Today we're following the astronomer Pytheas, who in about 300 BCE went on a journey of discovery to the far north, following the tin route. His book "On the Ocean" unfortunately got lost, but we know from other accounts that he made his way to Britain and from there, Barbarians showed him "where the sun goes to rest": another six day journey across the sea and there was the island he called Thule. It has been assumed for a long time that Thule must be Iceland, though in recent times, other theories have emerged, suggesting Smøla in Norway and Saaremaa in Estonia.