Editors. "Pope Sixtus V proclaims a Catholic Crusade to invade England". The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=15358, accessed 22 May 2013.]
Pope Sixtus V declares a Catholic Crusade to invade England and depose its Protestant monarch, Elizabeth I, under whose jurisdiction the execution of Mary Queen of Scots was carried out in February. Spain has been planning just such an invasion for some time, so eagerly takes up the challenge.