Stave churches were common in northwestern Europe in mediaeval times. In 2013 there were 28 remaining in Norway, dating back to the 12th and 13th centuries, but modified over the centuries.
Lomskyrkja – the church in Lom – is one of the largest and most beautiful stave churches in Norway. Its age has been confirmed by dendrochronological research.
The name for this type of church comes from its post and beam construction, a form of timber framing. The load-bearing ore-pine posts are called stafr in Old Norse (stav in modern Norwegian).
“The impressive church dates back to 1158-59, confirmed through dendrochronological research. It is still the main church in Lom. The oldest part was built in Romanesque style.The Lom stave church was built extra large; in the Middle Ages it was the main church in the northern Gudbrandsdal district. Lom was also an important stopover for pilgrims at that time. In 1634 the church was extended to the west, and in 1663 the cross arms were added in framework construction to the north and south. The tower was built at the same time. Most of the furnishing is from the 18th century. The famous wood carver Jakop Sæterdalen is the master behind the chancel arch and the pulpit. The Lom stave church has the largest collection of paintings found in any Norwegian church, most of them done by Eggert Munch. By archeological excavations in 1973 interesting findings were made; more than 2.000 coins and a love message with carved runes on a stick.” (https://www.visitnorway.com/listings/lom-stave-church/182786/)
“The church is a triple nave stave church that uses free standing inner columns to support a raised section in the ceiling of the main nave. This type of church is amongst the oldest Stave Churches. The church was first situated in a sub valley to the valley Gudbrandsdal in Oppland County, some 60 kilometers (37 mi) west of Otta. The church dates to approximately second part of 12th century. It was rebuilt into a cruciform church during the 17th century, which gave it the appearance it has retained since. The chancel was decorated in 1608, and the nave was enlarged towards west in 1634. The cross section was added in 1663, but this was made in stave like frame work. Master builder Werner Olsen (ca. 1600-1682) was engaged for the remodel and extension. He was active in Gudbrandsdal and had previously worked on Vågå church (1626–28) and Ringebu stave church (1630). A complete restoration also took place in 1933. An archaeological excavation was conducted in 1973 in connection with the repair of the floors. The excavations uncovered artifacts including more than 2,000 coins. At that same time, a renovation began to improve thermal insulation. This stave church is actually one of just a very few stave churches of which the original medieval crest with a dragon head still survives.” (https://en.wikipedia.org/wiki/Lom_Stave_Church)