Editors. "Protestant princes at the Diet of Ratisbon oppose imperial tax demands". The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=15526, accessed 22 May 2013.]
At the Diet of Ratisbon, the Archduke Matthias, who is there representing his brother Emperor Rudolf II, faces opposition from the German Protestant princes, who resent what they see as excessive demands for imperial taxation.