The following is from Aljo Wijnands, located at: http://www.home.zonnet.nl/Amersfoort/engels/enframes.html
A short history of Amersfoort. Before 777, very little is known about Amersfoort. Archeological digs produce very little material of that period, because of the properties of the soil. Leusden and the river Eem are first mentioned in the 'Bill of 777', when Karel de Great, seated in Nijmegen, donates estates in the Amersfoort area to the Bishop of Utrecht. In this document the name Flethite is mentioned which would later be changed in Flehite. The oldest part of Amersfoort is located in the higher areas between de Langestraat, de Krommestraat and 't Havik. In the early history of Amersfoort, the city used to be flooded when the river Eem went over its banks. So a sluice was constructed near the Koppelpoort, and het Spui. Amersfoort is first mentioned in 1028. At that time the Gelderse Valley was reclaimed, and Amersfoort became a bordertown. 1248 consecration St. Jorischurch. 1259 Cityrights. First wall completed 1300. Second wall completed 1450. Even before 1400 the Amersfoort harbour was moved from 't Havik to just outside the Koppelgate. 1579 end of Catholocism and adoption of the Protestant faith. After 1615 tobacco growing in the Amersfoort area. 1661 'de Kei' (the boulder) is pulled into the city.