Question: What other kingdom claimed ownership of the northern islands of scotland?

context: The culture that built the brochs is unknown, but by the late Iron Age the Northern Isles were part of the Pictish kingdom. The main archaeological relics from these times are symbol stones. One of the best examples is located on the Brough of Birsay; it shows three warriors with spears and sword scabbards combined with traditional Pictish symbols. The St Ninian's Isle Treasure was discovered in 1958. The silver bowls, jewellery and other pieces are believed to date from approximately 800 AD. O'Dell (1959) stated that "the treasure is the best survival of Scottish silver metalwork from the period" and that "the brooches show a variety of typical Pictish forms, with both animal-head and lobed geometrical forms of terminal".
question: What other kingdom claimed ownership of the northern islands of scotland until 875?
short_answers: Pictish kingdom
Pictish
Picts
context: No context provided
question: What other kingdom claimed ownership of the northern islands of scotland following an annexation in 875?
short_answers: Norwegian
Norway

Answer: Several kingdoms have claimed ownership of the northern islands of Scotland, a pair of archipelagos off the north coast of mainland Scotland known as the Northern Isles, including the Pictish kingdom and Norway. Prior to 875, the Pictish people, or Picts, a group of Celtic-speaking peoples who lived in what is now northern and eastern Scotland, claimed ownership of the Northern Isles. In 875, the Norwegian king Harald Hårfagre annexed the Northern Isles.