¹⁴"Review of "The Massacre at Smerwick" 1937." Ulster Journal of Archaeology 2 (1939): 127-28.
It seems that the English felt that they had no obligation to recognize the sovereignty of the Pope, who financed the expeditionary forces, and the King of Spain did not wish to be implicated in the attack. Thus the Catholic forces were thought of as bandits who were not deserving of the normal treatment specified for prisoners of war.