Olaf I of Norway
Olaf Tryggvason (960s – 9 September 1000) was King of Norway from 995 to 1000. He was the son of Tryggvi Olafsson, king of Viken (Vingulmark, and Rånrike), and, according to later sagas, the great-grandson of Harald Fairhair, first King of Norway. He is numbered as Olaf I.
Olaf is seen as an important factor in the conversion of the Norse to Christianity. He is said to have built the first Christian church in Norway, in 995, and to have founded the city of Trondheim in 997. A statue of Olaf Tryggvason is located in the city's central plaza.
Historical information on Olaf is sparse. He is mentioned in some contemporary English sources, and some skaldic poems. The oldest narrative source mentioning him briefly is Adam of Bremen's Gesta Hammaburgensis ecclesiae pontificum of circa 1070.
In the 1190s, two Latin versions of "Óláfs saga Tryggvasonar" were written in Iceland, by Oddr Snorrason and by Gunnlaugr Leifsson – these are now lost, but are thought to form the basis of later Norse versions. Snorri Sturluson gives an extensive account of Olaf in the Heimskringla saga of circa 1230, using Oddr Snorrason's saga as his primary source. Modern historians do not assume that these late sources are accurate, and their credibility is debated. The most detailed account is named Óláfs saga Tryggvasonar en mesta ("Greatest Saga of Óláfr Tryggvason") and is recorded in the Flateyjarbók, and in the early 15th-century Bergsbók.