Lövstabruk was once Sweden's largest ironworks and one of the world's leading. Already in the Middle Ages, iron began to be processed in Lövstabruk. During the 16th century, there was a farm on the site that was run by farmers in Österlövsta parish. At the end of the century, the crown mill Lövsta was established. Along with Österby mill and Gimo mill, Lövstabruk was leased out in 1626-27 to the Dutch merchants Willem de Besche and Louis de Geer. In 1643, Louis De Geer became the owner of Lövstabruk and also moved part of his business to Sweden.