Oeselians or Osilians is a historical name for the people who prior to the Northern Crusades in the 13th century lived in the Estonian island of Saaremaa (Ösel) – the Baltic Sea island was also referred as Oeselia or Osilia in written records dating from around that time. In Viking Age literature, the inhabitants were often included under the name "Vikings from Estonia", as written by Saxo Grammaticus in the late 12th century. The earliest known use of the word in the (Latinised) form of "Oeselians" in writing was by Henry of Livonia in the 13th century. The inhabitants of Saaremaa (Ösel) are also mentioned in a number of historic written sources dating from the Estonian Viking Age.
On the eve of Northern Crusades, the people then residing in Saaremaa were described in the Livonian Rhymed Chronicle: "The Oeselians, neighbors to the Kurs (Curonians), are surrounded by the sea and never fear strong armies as their strength is in their ships. In summers when they can travel across the sea they oppress the surrounding lands by raiding both Christians and pagans."
