Brochs are popularly associated with the Picts. Although these were built earlier in the Iron Age, with construction ending around 100 AD, they remained in use into and beyond the Pictish period. Crannogs, which may originate in Neolithic Scotland, may have been rebuilt, and some were still in use in the time of the Picts. The most common sort of buildings would have been roundhouses and rectangular timbered halls. While many churches were built in wood, from the early 8th century, if not earlier, some were built in stone.