southern Espoo, which formed an archipelago at the time. When ironwork was introduced to Finland around 500 BCE, it gave people access to materials that were far more versatile than materials used before. However, the climate grew colder at the beginning of the Iron Age, and it seems that human settlement in Espoo disappeared during the era. Only two discoveries from the time have been made in Espoo. Swedish rule Medieval Espoo Most of the original villages of present-day Espoo were founded by Tavastian Finns according to place names. By the 12th century, there were Tavastian houses on the shore of Kaukjärvi (now known as Pitkäjärvi), in Kauklahti, Karvasmäki, Bemböle, Haapalahti and Finnevik. The first Swedish settlements in Uusimaa were established during the 12th or 13th century. Swedish settlers moved to the area through the current site of Kirkkonummi, and then to the Esboby area. From there, they continued northeast to Kauklahti, Bemböle and Vanhakartano. In later stages, settlers might also have arrived in Espoo directly from Sweden, most likely from Svealand. The Swedish name for Espoo, Esbo, dates from this period. The settlers changed the Finnish names used by the Tavastians to Swedish ones: for example Kauklahti became Köklax and Karvasmäki became Karvasbacka. The current Finnish names might also have changed from the original ones in this process. For example, the place name Välli might have been changed into Vällskog, which has since led to the current Finnish name Velskola. The Swedish settlements were so extensive that the entire area became Swedish-speaking, except for its northernmost part and possibly the Haapalahti-Mäkkylä area. Palynological analyses indicate that agriculture was already practised in Espoo around the 11th century, but no historical records from the era survive. Until the late 13th century, Espoo was part of a borderland region between the Southwestern Finns and Tavastian Finns. Some artefacts found in Espoo have also been traced to ancient Savo-Karelian Finnish costumes, and the Late Iron Age and Early Medieval women in the area have had similar jewellery as in the region around present-day Mikkeli. In the Middle Ages, there were about 70 village lots in Espoo. Ancient fields and many passageways have been discovered near the remains of ancient villages. Espaby (at which site the Espoo manor was later founded) was probably the oldest Swedish-speaking village in the area. The name Espoo likely refers to the name of the river Espoonjoki (Swedish: Esboån,