Charles V had failed to secure the imperial succession for his son. But the fact of empire was not changed by this failure. Philip II still ruled over Spain and her dependencies in Italy, Franche-Comté, the Netherlands and the Indies. These had been the main sources of Charles V's imperial strength, of his money and his soldiers. Materially, at least, it was to Philip's advantage to disengage Spanish policy from the problems of central Europe while, at the same time, keeping on amicable terms with his uncle and cousins of the Austrian branch of the Habsburg family. His marriage to Mary I of England (1554) was the logical complement to such a policy and even after Mary's death (1558) it was not immediately obvious that England would not remain, or become again, a Habsburg satellite. But the absence of the imperial title raised its own difficulties about the nature of Philip II's empire. Charles V's views of the transcendental nature of his position and of his destiny to create a Christian world monarchy had depended on this title. What was left for Philip II was another part of his father's mission, the defence of the Catholic church. ‘You may assure His Holiness’, Philip wrote to his ambassador in Rome in 1566, ‘that rather than suffer the least damage to religion and the service of God, I would lose all my states and an hundred lives, if I had them; for I do not propose nor desire to be the ruler of heretics.’