(1587–1652)
Born in Liege, Southern Netherlands, de Geer and his parents established themselves in Amsterdam. He became one of the wealthiest merchants in the commerce of iron and weapons, especially during the Thirty Years’ War (1618–1648). To gether with his brother-in-law, he organized iron mining in Sweden, where he settled. He became an important financier of the Swedish king and as such acquired influence in Swedish foreign policy.
Historical Dictionary of the Netherlands. EdwART. 2012.