Complex sentence: The founder, Anders Sandvig, collected old houses and farmyards from the Gudbrandsdalen valley to sample Norwegian culture and history in a museum-first in his backyard, but when his collection grew, the town council offered him a permanent site for the museum in 1901.
Split into simpler sentences: The founder, Anders Sandvig, collected from old houses and farmyards within the Gudbrandsdalen valley to provide a sample of Norwegian culture and history in a museum. He start first in his backyard, but when his collection grew, the town council offered him a permanent site for the museum in 1901.