The region of Selonia (Sēlija) and the history of Selonians is a yet unresolved mystery. The ancient lands of Selonians are rich in beautiful natural landscapes and unique history, witnessed by ancient and spectacular Selonian hillforts. The history of Selonians can be traced back several millennia. The earliest written testimony of Selonians is found in The Chronicle of Henry of Livonia of the 13th century.
Selonians were a nation of farmers, who inhabited about 10–15 hillforts in the middle and late Iron Age. Their peculiarity is the common terraces that are not characteristic of other places and form an additional protection system, thus replacing the castlefronts.