ORIGINAL ARTICLE History of agriculture in Mikkeli Orija ¨rvi, eastern Finland as reflected by palynological and archaeological data Teija Alenius Æ Esa Mikkola Æ Antti E. K. Ojala Received: 21 April 2006 / Accepted: 13 November 2006 / Published online: 8 March 2007 Ó Springer-Verlag 2007 Abstract The introduction and development of cultiva- tion in eastern Finland was studied by pollen and charcoal analysis of a palaeomagnetically dated sediment profile from Lake Orija ¨rvi, in the vicinity of permanent prehistoric fields. The earliest changes of possibly anthropogenic ori- gin are visible in the pollen data from 1630 B.C. onwards and indications of human impact become more evident from 500 B.C. onwards. According to finds of cereal pollen and AMS-dating of charred cereal grains from the oldest field layer, the onset of cultivation can be dated to the Merovingian period around A.D. 600. To a significant extent the pollen data reflect only the cultivation of Secale during the first 600 years. The marked intensification of agricul- tural activities including cultivation in permanent fields only becomes evident in the pollen data from about A.D. 1050 to 1080 onwards and the most intensive land use phase dates to A.D. 1300–1965. Archaeological and palae- oecological material indicate that swidden cultivation and permanent field cultivation were in use simultaneously during the late Iron Age. The combination of these tech- niques together with animal husbandry and hunting formed a subsistence strategy in the climatic border-zone outside the centres of the agricultural core areas. Keywords Pollen Á Palaeomagnetic dating Á Iron Age Á Prehistoric fields Á Swidden cultivation Á Permanent field cultivation Introduction Lake Orija ¨rvi (27°14¢E, 61°40¢N) is located in eastern Finland in the province of South Savo, ca. 4 km from the centre of the city of Mikkeli. An Iron Age dwelling site, which was later named Orija ¨rvi Kihlinpelto, was found by local amateur archaeologists on the northern side of the lake in 1998. Initially, an Ottonian silver coin minted in Cologne (Mikkola and Talvio 2000) was found in the vicinity of the Kihli farmhouse, ca. 300 m from the lake, on a terrace-like platform that lies ca. 12 m above the present water level of the lake (Fig. 1). The landscape of the area, which has changed dramatically in recent years due to local development events, consisted of the farm, surrounded by a relatively large and open field sloping slightly (<5%) towards the south and west, with hilly woodland areas in the east and north. In 1999 a trial excavation was carried out at the site. Further excavations were subsequently carried out by the National Board of Antiquities in 2000, 2002, 2003 and 2005. In these rescue excavations over 260 features and structures including five ancient fields have been found. The fields (Fig. 2) form two separate larger units, the Karilantie field complex and the Peltorannantie field complex. The former, which has been fully excavated, consists of three adjacent fields dating to the middle and late Iron Age and early Middle Ages (ca. A.D. 600–1200). The fields formed a single unit during the early Middle Ages. The latter complex consists of two adjacent fields that have been only partially excavated. Peltorannantie Communicated by B. Aaby. T. Alenius (&) Á A. E. K. Ojala Geological Survey of Finland, P.O. Box 96, 02151 Espoo, Finland e-mail: teija.alenius@gtk.fi E. Mikkola National Board of Antiquities, P.O. Box 913, 00101 Helsinki, Finland 123 Veget Hist Archaeobot (2008) 17:171–183 DOI 10.1007/s00334-007-0099-5