Complex sentence: Somerled's grandsons were the first of Clan Donald and Mac Dougall, at it was around this time that clan MacInnes was awarded its name as MacInnes or' sons of chosen one.
Split into simpler sentences: Somerled's grandsons were the first of Clan Donald and Mac Dougall. It was around this time that clan MacInnes was awarded its name as MacInnes or' sons of chosen one.