Henry VIII is granted the title 'Defender of the Faith' by Pope Leo
X, in response to his book 'Assertio Septem Sacramentorum', which
defended the Church's doctrine of the seven sacraments against the
attacks of Martin Luther.
Citation:
Editors. "Pope Leo X confers the title 'Defender of the Faith' on Henry VIII".
The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14282, accessed 19 June 2013.]