Complex sentence: Cannibalism was not uncommon in those times and although Pettersson was uncommonly strong, he would not have been a match for them, but the islanders carried him to their king, and the king's daughter fell in love with him.
Split into simpler sentences: Cannibalism was not uncommon in those times and although Pettersson was uncommonly strong, he would not have been a match for them. The islanders carried him to their king, and the king's daughter fell in love with him.