Vegetation history of a primeval forest (Fiby urskog) in south Sweden is outlined from a paleoecological perspective. Pollen, spores, charcoal fragments and mineral particles were analyzed from a small, centrally placed wetland basin. C-14 dating, diatom analysis and shore displacement data aided in dating the vegetation succession. Indicators of human impact and other disturbances, during the last ca 1000 years, are given particular attention, as well as Picea immigration. Elevated parts of Fiby area rose above the Littorina Sea level ca 7000 BP. Early establishing forest included Pinus, Betula, Alnus and Quercetum mixtum forest species. The wetland basin became isolated ca 5800 cal. yr BP. Drier conditions eventually permitted woody species such as Alnus and Betula to enter the basin from ca 4540 cal. yr BP, or earlier. Sedimentation stopped in the contemporary warm and dry conditions creating an hiatus. Paludification occurred and sedimentation resumed from ca 2600 cal. yr BP, turning the basin into Sphagnum fen with Menyanthes trifoliata, Lysimachia and Carex spp. Pinus and Betula maintained strong presence though some species, particularly Alnus, continued a decreasing trend. Fires were mainly restricted to bedrock outcrops. Last extensive fires were at ca 600 and 400 cal. yr BP. A much delayed Picea immigration commenced from ca 300 cal. yr BP, accompanied by a decline in forest fires. Occasional cereal and weed pollen indicating agricultural activity appear, but are considered as imports from surrounding landscapes. Gap phase dynamics evolve as the most important disturbance factor in the final Picea dominated forest.