 He then joined the Freikorps for a spell before being discharged from the new Reichswehr after its numbers were substantially reduced by the terms of the Treaty of Versailles.The demobbed Ilgner took a doctorate in political science at the Goethe University Frankfurt, having also studied metallurgy and chemistry at the Technical College of Charlottenburg.He briefly worked in Stockholm following completion of his studies and whilst there he met Werna Gudrun Hällström.