The buildings became larger and more prominent, culminating in the brochs – circular, dry-stone towers belonging to the local chieftains – testifying to the uncertain nature of life then.
The island's diverse habitats are home to an assortment of flora and fauna, such as the golden eagle, red deer and seal, and are recognised in a number of conservation areas.
The people were called the Norse Gaels or Gall-Ghàidheil (lit.
"Foreigner Gaels"), reflecting their mixed Scandinavian/Gaelic background, and probably their bilingual speech.
The Norse language persists in many island placenames and some personal names to this day, although the latter are fairly evenly spread across the Gàidhealtachd.
Lewis (and the rest of the Western Isles) became part of Scotland once more in 1266: under the Treaty of Perth it was ceded by the Kingdom of Norway.