Complex sentence: He bequeathed his collection to the state with provision for its upkeep and for assistance to Icelandic students, which forms the basis of the Arnamagnæan Institute and associated stipends.
Split into simpler sentences: He bequeathed his collection to the state with provision for its upkeep and for assistance to Icelandic students. It forms the basis of the Arnamagnæan Institute and associated stipends.