Editors. "Heidelberg surrenders to the imperialists". The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=15893, accessed 21 April 2014.]
In the Thirty Years War, the German city of Heidelberg is forced to surrender to the Imperial army. James I sends diplomat Endymion Porter to Spain, with the aim of encouraging Philip IV to persuade Emperor Ferdinand II that Heidelberg should be restored to the Elector Palatine within 70 days, but this mission achieves nothing.