Avaldsnes Church (, formally St. Olav's Church at Avaldsnes, ) is a parish church of the Church of Norway in Karmøy Municipality in Rogaland county, Norway. It is located in the village of Avaldsnes on the northern part of the island of Karmøy. It is the church for the Avaldsnes parish which is part of the Karmøy prosti (deanery) in the Diocese of Stavanger. The medieval stone church was built in a long church design by an unknown architect. The first church located here was likely built before the year 1024 on the site of Avaldsnes Kongsgård estate. The present stone church was built in 1250. The church seats about 400 people. History Before this church was constructed, there was a wooden church on the same site around the year 1024. That church is assumed to have been built by Olav Trygvason, and it is possible that the present stone church is built around this church originally. The church was mentioned by the historian Snorri Sturluson in chapter 19 of his book Soga om Olav den heilage. This church has been a landmark for seafarers passing through the Karmsundet strait for 750 years. King Håkon IV Håkonsson gave permission to replace the old wooden church with a stone church around the year 1250. The new stone building was not completed until nearly 1320, and was then the fourth largest in the country. The church was dedicated to St. Olav and received the status of "Royal Chapel". During the same period it became one of four "college-churches" (it appointed a council of theological and juridical scholars). Probably there was a group of four scholars and teachers in law and theology. The stone church had a rectangular nave and narrower, rectangular chancel as well as a large tower to the west. There was an octagonal stone room located to the south of the quire. This octagonal room was a chapter house (kapittelhus). These rooms were common for English cathedrals and they were used for large group meetings. This room is assumed to have been referenced in 1599 by clergyman and historical writer Peder Claussøn Friis (1545–1614). Remaining walls for this room were visible as late as 1840, but are now completely gone. Decay started with the Black Death in 1349–1351. This disaster was followed by 400 years of Danish supremacy. In this period, the church gradually fell into a state of ruin